diff --git a/Cargo.lock b/Cargo.lock
index 5e4ee86553d4b6..966f531e404278 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -4953,6 +4953,7 @@ dependencies = [
  "futures",
  "hyper",
  "lazy_static",
+ "lsp-types",
  "once_cell",
  "os_pipe",
  "parking_lot 0.12.1",
diff --git a/Cargo.toml b/Cargo.toml
index 1c6bb90f8e4458..d3020cc55ad31c 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -95,6 +95,7 @@ hyper = "0.14.18"
 indexmap = { version = "1.9.2", features = ["serde"] }
 libc = "0.2.126"
 log = "=0.4.17"
+lsp-types = "=0.93.2" # used by tower-lsp and "proposed" feature is unstable in patch releases
 lzzzz = "1.0"
 notify = "=5.0.0"
 once_cell = "1.17.1"
@@ -122,6 +123,7 @@ tokio = { version = "=1.25.0", features = ["full"] }
 tokio-rustls = "0.23.3"
 tokio-tungstenite = "0.16.1"
 tokio-util = "0.7.4"
+tower-lsp = { version = "=0.17.0", features = ["proposed"] }
 url = { version = "2.3.1", features = ["serde", "expose_internals"] }
 uuid = { version = "1.3.0", features = ["v4"] }
 zstd = "=0.11.2"
diff --git a/cli/Cargo.toml b/cli/Cargo.toml
index c38105cfe12ddb..65e4359c2e03ac 100644
--- a/cli/Cargo.toml
+++ b/cli/Cargo.toml
@@ -80,7 +80,7 @@ indexmap.workspace = true
 jsonc-parser = { version = "=0.21.0", features = ["serde"] }
 libc.workspace = true
 log = { workspace = true, features = ["serde"] }
-lsp-types = "=0.93.2" # used by tower-lsp and "proposed" feature is unstable in patch releases
+lsp-types.workspace = true
 lzzzz = '1.0'
 mitata = "=0.0.7"
 monch = "=0.4.1"
@@ -104,7 +104,7 @@ text_lines = "=0.6.0"
 thiserror = "=1.0.38"
 tokio.workspace = true
 tokio-util.workspace = true
-tower-lsp = { version = "=0.17.0", features = ["proposed"] }
+tower-lsp.workspace = true
 twox-hash = "=1.6.3"
 typed-arena = "=2.0.1"
 uuid = { workspace = true, features = ["serde"] }
diff --git a/cli/bench/lsp.rs b/cli/bench/lsp.rs
index 722a87b69bf9aa..b0682e2e924978 100644
--- a/cli/bench/lsp.rs
+++ b/cli/bench/lsp.rs
@@ -9,15 +9,13 @@ use deno_core::url::Url;
 use std::collections::HashMap;
 use std::path::Path;
 use std::time::Duration;
-use test_util::lsp::LspClient;
+use test_util::lsp::LspClientBuilder;
 use test_util::lsp::LspResponseError;
 use tower_lsp::lsp_types as lsp;
 
 static FIXTURE_CODE_LENS_TS: &str = include_str!("testdata/code_lens.ts");
 static FIXTURE_DB_TS: &str = include_str!("testdata/db.ts");
 static FIXTURE_DB_MESSAGES: &[u8] = include_bytes!("testdata/db_messages.json");
-static FIXTURE_INIT_JSON: &[u8] =
-  include_bytes!("testdata/initialize_params.json");
 
 #[derive(Debug, Deserialize)]
 enum FixtureType {
@@ -44,14 +42,8 @@ struct FixtureMessage {
 /// the end of the document and does a level of hovering and gets quick fix
 /// code actions.
 fn bench_big_file_edits(deno_exe: &Path) -> Result<Duration, AnyError> {
-  let mut client = LspClient::new(deno_exe, false)?;
-
-  let params: Value = serde_json::from_slice(FIXTURE_INIT_JSON)?;
-  let (_, response_error): (Option<Value>, Option<LspResponseError>) =
-    client.write_request("initialize", params)?;
-  assert!(response_error.is_none());
-
-  client.write_notification("initialized", json!({}))?;
+  let mut client = LspClientBuilder::new().deno_exe(deno_exe).build();
+  client.initialize_default();
 
   client.write_notification(
     "textDocument/didOpen",
@@ -125,13 +117,8 @@ fn bench_big_file_edits(deno_exe: &Path) -> Result<Duration, AnyError> {
 }
 
 fn bench_code_lens(deno_exe: &Path) -> Result<Duration, AnyError> {
-  let mut client = LspClient::new(deno_exe, false)?;
-
-  let params: Value = serde_json::from_slice(FIXTURE_INIT_JSON)?;
-  let (_, maybe_err) =
-    client.write_request::<_, _, Value>("initialize", params)?;
-  assert!(maybe_err.is_none());
-  client.write_notification("initialized", json!({}))?;
+  let mut client = LspClientBuilder::new().deno_exe(deno_exe).build();
+  client.initialize_default();
 
   client.write_notification(
     "textDocument/didOpen",
@@ -189,13 +176,8 @@ fn bench_code_lens(deno_exe: &Path) -> Result<Duration, AnyError> {
 }
 
 fn bench_find_replace(deno_exe: &Path) -> Result<Duration, AnyError> {
-  let mut client = LspClient::new(deno_exe, false)?;
-
-  let params: Value = serde_json::from_slice(FIXTURE_INIT_JSON)?;
-  let (_, maybe_err) =
-    client.write_request::<_, _, Value>("initialize", params)?;
-  assert!(maybe_err.is_none());
-  client.write_notification("initialized", json!({}))?;
+  let mut client = LspClientBuilder::new().deno_exe(deno_exe).build();
+  client.initialize_default();
 
   for i in 0..10 {
     client.write_notification(
@@ -285,14 +267,8 @@ fn bench_find_replace(deno_exe: &Path) -> Result<Duration, AnyError> {
 
 /// A test that starts up the LSP, opens a single line document, and exits.
 fn bench_startup_shutdown(deno_exe: &Path) -> Result<Duration, AnyError> {
-  let mut client = LspClient::new(deno_exe, false)?;
-
-  let params: Value = serde_json::from_slice(FIXTURE_INIT_JSON)?;
-  let (_, response_error) =
-    client.write_request::<_, _, Value>("initialize", params)?;
-  assert!(response_error.is_none());
-
-  client.write_notification("initialized", json!({}))?;
+  let mut client = LspClientBuilder::new().deno_exe(deno_exe).build();
+  client.initialize_default();
 
   client.write_notification(
     "textDocument/didOpen",
diff --git a/cli/bench/lsp_bench_standalone.rs b/cli/bench/lsp_bench_standalone.rs
index e8dc2907309701..888d959ace210a 100644
--- a/cli/bench/lsp_bench_standalone.rs
+++ b/cli/bench/lsp_bench_standalone.rs
@@ -3,25 +3,16 @@
 use deno_bench_util::bencher::benchmark_group;
 use deno_bench_util::bencher::benchmark_main;
 use deno_bench_util::bencher::Bencher;
-use deno_core::serde_json;
 use deno_core::serde_json::json;
 use deno_core::serde_json::Value;
 use test_util::lsp::LspClient;
+use test_util::lsp::LspClientBuilder;
 
 // Intended to match the benchmark in quick-lint-js
 // https://github.com/quick-lint/quick-lint-js/blob/35207e6616267c6c81be63f47ce97ec2452d60df/benchmark/benchmark-lsp/lsp-benchmarks.cpp#L223-L268
 fn incremental_change_wait(bench: &mut Bencher) {
-  let deno_exe = test_util::deno_exe_path();
-  let mut client = LspClient::new(&deno_exe, false).unwrap();
-
-  static FIXTURE_INIT_JSON: &[u8] =
-    include_bytes!("testdata/initialize_params.json");
-  let params: Value = serde_json::from_slice(FIXTURE_INIT_JSON).unwrap();
-  let (_, maybe_err) = client
-    .write_request::<_, _, Value>("initialize", params)
-    .unwrap();
-  assert!(maybe_err.is_none());
-  client.write_notification("initialized", json!({})).unwrap();
+  let mut client = LspClientBuilder::new().build();
+  client.initialize_default();
 
   client
     .write_notification(
diff --git a/cli/tests/integration/lsp_tests.rs b/cli/tests/integration/lsp_tests.rs
index 9a62e42a378811..344ba0804fc0b1 100644
--- a/cli/tests/integration/lsp_tests.rs
+++ b/cli/tests/integration/lsp_tests.rs
@@ -1,7 +1,6 @@
 // Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
 
 use deno_ast::ModuleSpecifier;
-use deno_core::serde::de::DeserializeOwned;
 use deno_core::serde::Deserialize;
 use deno_core::serde::Serialize;
 use deno_core::serde_json;
@@ -13,42 +12,13 @@ use std::collections::HashSet;
 use std::fs;
 use std::process::Stdio;
 use test_util::deno_cmd_with_deno_dir;
-use test_util::deno_exe_path;
 use test_util::env_vars_for_npm_tests;
-use test_util::http_server;
 use test_util::lsp::LspClient;
+use test_util::lsp::LspClientBuilder;
 use test_util::testdata_path;
-use test_util::TempDir;
+use test_util::TestContextBuilder;
 use tower_lsp::lsp_types as lsp;
 
-fn load_fixture(path: &str) -> Value {
-  load_fixture_as(path)
-}
-
-fn load_fixture_as<T>(path: &str) -> T
-where
-  T: DeserializeOwned,
-{
-  let fixture_str = load_fixture_str(path);
-  serde_json::from_str::<T>(&fixture_str).unwrap()
-}
-
-fn load_fixture_str(path: &str) -> String {
-  let fixtures_path = testdata_path().join("lsp");
-  let path = fixtures_path.join(path);
-  fs::read_to_string(path).unwrap()
-}
-
-fn init(init_path: &str) -> LspClient {
-  let deno_exe = deno_exe_path();
-  let mut client = LspClient::new(&deno_exe, false).unwrap();
-  client
-    .write_request::<_, _, Value>("initialize", load_fixture(init_path))
-    .unwrap();
-  client.write_notification("initialized", json!({})).unwrap();
-  client
-}
-
 fn did_open<V>(
   client: &mut LspClient,
   params: V,
@@ -91,34 +61,13 @@ fn read_diagnostics(client: &mut LspClient) -> CollectedDiagnostics {
   CollectedDiagnostics(diagnostics)
 }
 
-fn shutdown(client: &mut LspClient) {
-  client
-    .write_request::<_, _, Value>("shutdown", json!(null))
-    .unwrap();
-  client.write_notification("exit", json!(null)).unwrap();
-}
-
-pub fn ensure_directory_specifier(
-  mut specifier: ModuleSpecifier,
-) -> ModuleSpecifier {
-  let path = specifier.path();
-  if !path.ends_with('/') {
-    let new_path = format!("{path}/");
-    specifier.set_path(&new_path);
-  }
-  specifier
-}
-
+// todo(dsherret): get rid of this in favour of LspClient
 struct TestSession {
   client: LspClient,
   open_file_count: usize,
 }
 
 impl TestSession {
-  pub fn from_file(init_path: &str) -> Self {
-    Self::from_client(init(init_path))
-  }
-
   pub fn from_client(client: LspClient) -> Self {
     Self {
       client,
@@ -163,7 +112,7 @@ impl TestSession {
   }
 
   pub fn shutdown_and_exit(&mut self) {
-    shutdown(&mut self.client);
+    self.client.shutdown();
   }
 }
 
@@ -230,32 +179,29 @@ impl CollectedDiagnostics {
 
 #[test]
 fn lsp_startup_shutdown() {
-  let mut client = init("initialize_params.json");
-  shutdown(&mut client);
+  let mut client = LspClientBuilder::new().build();
+  client.initialize_default();
+  client.shutdown();
 }
 
 #[test]
 fn lsp_init_tsconfig() {
-  let temp_dir = TempDir::new();
-  let mut params: lsp::InitializeParams =
-    serde_json::from_value(load_fixture("initialize_params.json")).unwrap();
-  let tsconfig =
-    serde_json::to_vec_pretty(&load_fixture("lib.tsconfig.json")).unwrap();
-  fs::write(temp_dir.path().join("lib.tsconfig.json"), tsconfig).unwrap();
-
-  params.root_uri = Some(Url::from_file_path(temp_dir.path()).unwrap());
-  if let Some(Value::Object(mut map)) = params.initialization_options {
-    map.insert("config".to_string(), json!("./lib.tsconfig.json"));
-    params.initialization_options = Some(Value::Object(map));
-  }
+  let context = TestContextBuilder::new().build();
+  let temp_dir = context.deno_dir();
 
-  let deno_exe = deno_exe_path();
-  let mut client = LspClient::new(&deno_exe, false).unwrap();
-  client
-    .write_request::<_, _, Value>("initialize", params)
-    .unwrap();
+  temp_dir.write(
+    "lib.tsconfig.json",
+    r#"{
+  "compilerOptions": {
+    "lib": ["deno.ns", "deno.unstable", "dom"]
+  }
+}"#,
+  );
 
-  client.write_notification("initialized", json!({})).unwrap();
+  let mut client = context.new_lsp_command().build();
+  client.initialize(|builder| {
+    builder.set_config("lib.tsconfig.json");
+  });
 
   let diagnostics = did_open(
     &mut client,
@@ -272,33 +218,34 @@ fn lsp_init_tsconfig() {
   let diagnostics = diagnostics.into_iter().flat_map(|x| x.diagnostics);
   assert_eq!(diagnostics.count(), 0);
 
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_tsconfig_types() {
-  let mut params: lsp::InitializeParams =
-    serde_json::from_value(load_fixture("initialize_params.json")).unwrap();
-  let temp_dir = TempDir::new();
-  let tsconfig =
-    serde_json::to_vec_pretty(&load_fixture("types.tsconfig.json")).unwrap();
-  fs::write(temp_dir.path().join("types.tsconfig.json"), tsconfig).unwrap();
-  let a_dts = load_fixture_str("a.d.ts");
-  fs::write(temp_dir.path().join("a.d.ts"), a_dts).unwrap();
-
-  params.root_uri = Some(Url::from_file_path(temp_dir.path()).unwrap());
-  if let Some(Value::Object(mut map)) = params.initialization_options {
-    map.insert("config".to_string(), json!("./types.tsconfig.json"));
-    params.initialization_options = Some(Value::Object(map));
-  }
+  let context = TestContextBuilder::new().build();
+  let temp_dir = context.deno_dir();
 
-  let deno_exe = deno_exe_path();
-  let mut client = LspClient::new(&deno_exe, false).unwrap();
-  client
-    .write_request::<_, _, Value>("initialize", params)
-    .unwrap();
+  temp_dir.write(
+    "types.tsconfig.json",
+    r#"{
+  "compilerOptions": {
+    "types": ["./a.d.ts"]
+  },
+  "lint": {
+    "rules": {
+      "tags": []
+    }
+  }
+}"#,
+  );
+  let a_dts = "// deno-lint-ignore-file no-var\ndeclare var a: string;";
+  temp_dir.write("a.d.ts", a_dts);
 
-  client.write_notification("initialized", json!({})).unwrap();
+  let mut client = context.new_lsp_command().build();
+  client.initialize(|builder| {
+    builder.set_config("types.tsconfig.json");
+  });
 
   let diagnostics = did_open(
     &mut client,
@@ -315,12 +262,17 @@ fn lsp_tsconfig_types() {
   let diagnostics = diagnostics.into_iter().flat_map(|x| x.diagnostics);
   assert_eq!(diagnostics.count(), 0);
 
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_tsconfig_bad_config_path() {
-  let mut client = init("initialize_params_bad_config_option.json");
+  let mut client = LspClientBuilder::new().build();
+  client.initialize(|builder| {
+    builder
+      .set_config("bad_tsconfig.json")
+      .set_maybe_root_uri(None);
+  });
   let (method, maybe_params) = client.read_notification().unwrap();
   assert_eq!(method, "window/showMessage");
   assert_eq!(maybe_params, Some(lsp::ShowMessageParams {
@@ -344,27 +296,18 @@ fn lsp_tsconfig_bad_config_path() {
 
 #[test]
 fn lsp_triple_slash_types() {
-  let temp_dir = TempDir::new();
-  let mut params: lsp::InitializeParams =
-    serde_json::from_value(load_fixture("initialize_params.json")).unwrap();
-  let a_dts = load_fixture_str("a.d.ts");
-  fs::write(temp_dir.path().join("a.d.ts"), a_dts).unwrap();
-
-  params.root_uri = Some(Url::from_file_path(temp_dir.path()).unwrap());
-
-  let deno_exe = deno_exe_path();
-  let mut client = LspClient::new(&deno_exe, false).unwrap();
-  client
-    .write_request::<_, _, Value>("initialize", params)
-    .unwrap();
-
-  client.write_notification("initialized", json!({})).unwrap();
+  let context = TestContextBuilder::new().build();
+  let temp_dir = context.deno_dir();
+  let a_dts = "// deno-lint-ignore-file no-var\ndeclare var a: string;";
+  temp_dir.write("a.d.ts", a_dts);
+  let mut client = context.new_lsp_command().build();
+  client.initialize_default();
 
   let diagnostics = did_open(
     &mut client,
     json!({
       "textDocument": {
-        "uri": Url::from_file_path(temp_dir.path().join("test.ts")).unwrap(),
+        "uri": temp_dir.uri().join("test.ts").unwrap(),
         "languageId": "typescript",
         "version": 1,
         "text": "/// <reference types=\"./a.d.ts\" />\n\nconsole.log(a);\n"
@@ -375,37 +318,27 @@ fn lsp_triple_slash_types() {
   let diagnostics = diagnostics.into_iter().flat_map(|x| x.diagnostics);
   assert_eq!(diagnostics.count(), 0);
 
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_import_map() {
-  let temp_dir = TempDir::new();
-  let mut params: lsp::InitializeParams =
-    serde_json::from_value(load_fixture("initialize_params.json")).unwrap();
-  let import_map =
-    serde_json::to_vec_pretty(&load_fixture("import-map.json")).unwrap();
-  fs::write(temp_dir.path().join("import-map.json"), import_map).unwrap();
-  fs::create_dir(temp_dir.path().join("lib")).unwrap();
-  fs::write(
-    temp_dir.path().join("lib").join("b.ts"),
-    r#"export const b = "b";"#,
-  )
-  .unwrap();
-
-  params.root_uri = Some(Url::from_file_path(temp_dir.path()).unwrap());
-  if let Some(Value::Object(mut map)) = params.initialization_options {
-    map.insert("importMap".to_string(), json!("import-map.json"));
-    params.initialization_options = Some(Value::Object(map));
+  let context = TestContextBuilder::new().build();
+  let temp_dir = context.deno_dir();
+  let import_map = r#"{
+  "imports": {
+    "/~/": "./lib/"
   }
+}"#;
+  temp_dir.write("import-map.json", import_map);
+  temp_dir.create_dir_all("lib");
+  temp_dir.write("lib/b.ts", r#"export const b = "b";"#);
 
-  let deno_exe = deno_exe_path();
-  let mut client = LspClient::new(&deno_exe, false).unwrap();
-  client
-    .write_request::<_, _, Value>("initialize", params)
-    .unwrap();
+  let mut client = context.new_lsp_command().build();
+  client.initialize(|builder| {
+    builder.set_import_map("import-map.json");
+  });
 
-  client.write_notification("initialized", json!({})).unwrap();
   let uri = Url::from_file_path(temp_dir.path().join("a.ts")).unwrap();
 
   let diagnostics = did_open(
@@ -430,10 +363,7 @@ fn lsp_import_map() {
         "textDocument": {
           "uri": uri
         },
-        "position": {
-          "line": 2,
-          "character": 12
-        }
+        "position": { "line": 2, "character": 12 }
       }),
     )
     .unwrap();
@@ -449,23 +379,21 @@ fn lsp_import_map() {
         ""
       ],
       "range": {
-        "start": {
-          "line": 2,
-          "character": 12
-        },
-        "end": {
-          "line": 2,
-          "character": 13
-        }
+        "start": { "line": 2, "character": 12 },
+        "end": { "line": 2, "character": 13 }
       }
     }))
   );
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_import_map_data_url() {
-  let mut client = init("initialize_params_import_map.json");
+  let context = TestContextBuilder::new().build();
+  let mut client = context.new_lsp_command().build();
+  client.initialize(|builder| {
+    builder.set_import_map("data:application/json;utf8,{\"imports\": { \"example\": \"https://deno.land/x/example/mod.ts\" }}");
+  });
   let diagnostics = did_open(
     &mut client,
     json!({
@@ -479,49 +407,42 @@ fn lsp_import_map_data_url() {
   );
 
   let mut diagnostics = diagnostics.into_iter().flat_map(|x| x.diagnostics);
-  // This indicates that the import map from initialize_params_import_map.json
-  // is applied correctly.
+  // This indicates that the import map is applied correctly.
   assert!(diagnostics.any(|diagnostic| diagnostic.code
     == Some(lsp::NumberOrString::String("no-cache".to_string()))
     && diagnostic
       .message
       .contains("https://deno.land/x/example/mod.ts")));
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_import_map_config_file() {
-  let temp_dir = TempDir::new();
-  let mut params: lsp::InitializeParams =
-    serde_json::from_value(load_fixture("initialize_params.json")).unwrap();
-
-  let deno_import_map_jsonc =
-    serde_json::to_vec_pretty(&load_fixture("deno.import_map.jsonc")).unwrap();
-  fs::write(
-    temp_dir.path().join("deno.import_map.jsonc"),
-    deno_import_map_jsonc,
-  )
-  .unwrap();
-
-  params.root_uri = Some(Url::from_file_path(temp_dir.path()).unwrap());
-  if let Some(Value::Object(mut map)) = params.initialization_options {
-    map.insert("config".to_string(), json!("./deno.import_map.jsonc"));
-    params.initialization_options = Some(Value::Object(map));
+  let context = TestContextBuilder::new().build();
+  let temp_dir = context.deno_dir();
+  temp_dir.write(
+    "deno.import_map.jsonc",
+    r#"{
+  "importMap": "import-map.json"
+}"#,
+  );
+  temp_dir.write(
+    "import-map.json",
+    r#"{
+  "imports": {
+    "/~/": "./lib/"
   }
-  let import_map_text =
-    serde_json::to_string_pretty(&load_fixture("import-map.json")).unwrap();
-  temp_dir.write("import-map.json", import_map_text);
+}"#,
+  );
   temp_dir.create_dir_all("lib");
   temp_dir.write("lib/b.ts", r#"export const b = "b";"#);
 
-  let deno_exe = deno_exe_path();
-  let mut client = LspClient::new(&deno_exe, false).unwrap();
-  client
-    .write_request::<_, _, Value>("initialize", params)
-    .unwrap();
+  let mut client = context.new_lsp_command().build();
+  client.initialize(|builder| {
+    builder.set_config("./deno.import_map.jsonc");
+  });
 
-  client.write_notification("initialized", json!({})).unwrap();
-  let uri = Url::from_file_path(temp_dir.path().join("a.ts")).unwrap();
+  let uri = temp_dir.uri().join("a.ts").unwrap();
 
   let diagnostics = did_open(
     &mut client,
@@ -545,10 +466,7 @@ fn lsp_import_map_config_file() {
         "textDocument": {
           "uri": uri
         },
-        "position": {
-          "line": 2,
-          "character": 12
-        }
+        "position": { "line": 2, "character": 12 }
       }),
     )
     .unwrap();
@@ -564,51 +482,35 @@ fn lsp_import_map_config_file() {
         ""
       ],
       "range": {
-        "start": {
-          "line": 2,
-          "character": 12
-        },
-        "end": {
-          "line": 2,
-          "character": 13
-        }
+        "start": { "line": 2, "character": 12 },
+        "end": { "line": 2, "character": 13 }
       }
     }))
   );
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_import_map_embedded_in_config_file() {
-  let temp_dir = TempDir::new();
-  let mut params: lsp::InitializeParams =
-    serde_json::from_value(load_fixture("initialize_params.json")).unwrap();
-
-  let deno_import_map_jsonc = serde_json::to_string_pretty(&load_fixture(
+  let context = TestContextBuilder::new().build();
+  let temp_dir = context.deno_dir();
+  temp_dir.write(
     "deno.embedded_import_map.jsonc",
-  ))
-  .unwrap();
-  temp_dir.write("deno.embedded_import_map.jsonc", deno_import_map_jsonc);
-
-  params.root_uri = Some(Url::from_file_path(temp_dir.path()).unwrap());
-  if let Some(Value::Object(mut map)) = params.initialization_options {
-    map.insert(
-      "config".to_string(),
-      json!("./deno.embedded_import_map.jsonc"),
-    );
-    params.initialization_options = Some(Value::Object(map));
+    r#"{
+  "imports": {
+    "/~/": "./lib/"
   }
-  fs::create_dir(temp_dir.path().join("lib")).unwrap();
+}"#,
+  );
+  temp_dir.create_dir_all("lib");
   temp_dir.write("lib/b.ts", r#"export const b = "b";"#);
 
-  let deno_exe = deno_exe_path();
-  let mut client = LspClient::new(&deno_exe, false).unwrap();
-  client
-    .write_request::<_, _, Value>("initialize", params)
-    .unwrap();
+  let mut client = context.new_lsp_command().build();
+  client.initialize(|builder| {
+    builder.set_config("./deno.embedded_import_map.jsonc");
+  });
 
-  client.write_notification("initialized", json!({})).unwrap();
-  let uri = Url::from_file_path(temp_dir.path().join("a.ts")).unwrap();
+  let uri = temp_dir.uri().join("a.ts").unwrap();
 
   let diagnostics = did_open(
     &mut client,
@@ -632,10 +534,7 @@ fn lsp_import_map_embedded_in_config_file() {
         "textDocument": {
           "uri": uri
         },
-        "position": {
-          "line": 2,
-          "character": 12
-        }
+        "position": { "line": 2, "character": 12 }
       }),
     )
     .unwrap();
@@ -651,44 +550,32 @@ fn lsp_import_map_embedded_in_config_file() {
         ""
       ],
       "range": {
-        "start": {
-          "line": 2,
-          "character": 12
-        },
-        "end": {
-          "line": 2,
-          "character": 13
-        }
+        "start": { "line": 2, "character": 12 },
+        "end": { "line": 2, "character": 13 }
       }
     }))
   );
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_deno_task() {
-  let temp_dir = TempDir::new();
-  let workspace_root = temp_dir.path().canonicalize().unwrap();
-  let mut params: lsp::InitializeParams =
-    serde_json::from_value(load_fixture("initialize_params.json")).unwrap();
-  fs::write(
-    workspace_root.join("deno.jsonc"),
+  let context = TestContextBuilder::new().build();
+  let temp_dir = context.deno_dir();
+  temp_dir.write(
+    "deno.jsonc",
     r#"{
     "tasks": {
       "build": "deno test",
       "some:test": "deno bundle mod.ts"
     }
   }"#,
-  )
-  .unwrap();
-
-  params.root_uri = Some(Url::from_file_path(workspace_root).unwrap());
+  );
 
-  let deno_exe = deno_exe_path();
-  let mut client = LspClient::new(&deno_exe, false).unwrap();
-  client
-    .write_request::<_, _, Value>("initialize", params)
-    .unwrap();
+  let mut client = context.new_lsp_command().build();
+  client.initialize(|builder| {
+    builder.set_config("./deno.jsonc");
+  });
 
   let (maybe_res, maybe_err) = client
     .write_request::<_, _, Value>("deno/task", json!(null))
@@ -701,8 +588,7 @@ fn lsp_deno_task() {
       {
         "name": "build",
         "detail": "deno test"
-      },
-      {
+      }, {
         "name": "some:test",
         "detail": "deno bundle mod.ts"
       }
@@ -712,7 +598,12 @@ fn lsp_deno_task() {
 
 #[test]
 fn lsp_import_assertions() {
-  let mut client = init("initialize_params_import_map.json");
+  let context = TestContextBuilder::new().build();
+  let mut client = context.new_lsp_command().build();
+  client.initialize(|builder| {
+    builder.set_import_map("data:application/json;utf8,{\"imports\": { \"example\": \"https://deno.land/x/example/mod.ts\" }}");
+  });
+
   client
     .write_notification(
       "textDocument/didOpen",
@@ -757,14 +648,8 @@ fn lsp_import_assertions() {
     json!([
       {
         "range": {
-          "start": {
-            "line": 0,
-            "character": 14
-          },
-          "end": {
-            "line": 0,
-            "character": 27
-          }
+          "start": { "line": 0, "character": 14 },
+          "end": { "line": 0, "character": 27 }
         },
         "severity": 1,
         "code": "no-assert-type",
@@ -777,47 +662,89 @@ fn lsp_import_assertions() {
   let (maybe_res, maybe_err) = client
     .write_request(
       "textDocument/codeAction",
-      load_fixture("code_action_params_import_assertion.json"),
+      json!({
+        "textDocument": {
+          "uri": "file:///a/a.ts"
+        },
+        "range": {
+          "start": { "line": 0, "character": 14 },
+          "end": { "line": 0, "character": 27 }
+        },
+        "context": {
+          "diagnostics": [{
+            "range": {
+              "start": { "line": 0, "character": 14 },
+              "end": { "line": 0, "character": 27 }
+            },
+            "severity": 1,
+            "code": "no-assert-type",
+            "source": "deno",
+            "message": "The module is a JSON module and not being imported with an import assertion. Consider adding `assert { type: \"json\" }` to the import statement."
+          }],
+          "only": ["quickfix"]
+        }
+      }),
     )
     .unwrap();
   assert!(maybe_err.is_none());
   assert_eq!(
     maybe_res,
-    Some(load_fixture("code_action_response_import_assertion.json"))
+    Some(json!([{
+      "title": "Insert import assertion.",
+      "kind": "quickfix",
+      "diagnostics": [
+        {
+          "range": {
+            "start": { "line": 0, "character": 14 },
+            "end": { "line": 0, "character": 27 }
+          },
+          "severity": 1,
+          "code": "no-assert-type",
+          "source": "deno",
+          "message": "The module is a JSON module and not being imported with an import assertion. Consider adding `assert { type: \"json\" }` to the import statement."
+        }
+      ],
+      "edit": {
+        "changes": {
+          "file:///a/a.ts": [
+            {
+              "range": {
+                "start": { "line": 0, "character": 27 },
+                "end": { "line": 0, "character": 27 }
+              },
+              "newText": " assert { type: \"json\" }"
+            }
+          ]
+        }
+      }
+    }]))
   );
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_import_map_import_completions() {
-  let temp_dir = TempDir::new();
-  let mut params: lsp::InitializeParams =
-    serde_json::from_value(load_fixture("initialize_params.json")).unwrap();
-  let import_map =
-    serde_json::to_vec_pretty(&load_fixture("import-map-completions.json"))
-      .unwrap();
-  fs::write(temp_dir.path().join("import-map.json"), import_map).unwrap();
-  fs::create_dir(temp_dir.path().join("lib")).unwrap();
-  fs::write(
-    temp_dir.path().join("lib").join("b.ts"),
-    r#"export const b = "b";"#,
-  )
-  .unwrap();
-
-  params.root_uri = Some(Url::from_file_path(temp_dir.path()).unwrap());
-  if let Some(Value::Object(mut map)) = params.initialization_options {
-    map.insert("importMap".to_string(), json!("import-map.json"));
-    params.initialization_options = Some(Value::Object(map));
+  let context = TestContextBuilder::new().build();
+  let temp_dir = context.deno_dir();
+  temp_dir.write(
+    "import-map.json",
+    r#"{
+  "imports": {
+    "/~/": "./lib/",
+    "fs": "https://example.com/fs/index.js",
+    "std/": "https://example.com/std@0.123.0/"
   }
+}"#,
+  );
+  temp_dir.create_dir_all("lib");
+  temp_dir.write("lib/b.ts", r#"export const b = "b";"#);
 
-  let deno_exe = deno_exe_path();
-  let mut client = LspClient::new(&deno_exe, false).unwrap();
-  client
-    .write_request::<_, _, Value>("initialize", params)
-    .unwrap();
+  let mut client = context.new_lsp_command().build();
+  client.initialize(|builder| {
+    builder.set_import_map("import-map.json");
+  });
 
-  client.write_notification("initialized", json!({})).unwrap();
-  let uri = Url::from_file_path(temp_dir.path().join("a.ts")).unwrap();
+  let uri = temp_dir.uri().join("a.ts").unwrap();
 
   did_open(
     &mut client,
@@ -838,10 +765,7 @@ fn lsp_import_map_import_completions() {
         "textDocument": {
           "uri": uri
         },
-        "position": {
-          "line": 1,
-          "character": 20
-        },
+        "position": { "line": 1, "character": 20 },
         "context": {
           "triggerKind": 2,
           "triggerCharacter": "\""
@@ -862,32 +786,28 @@ fn lsp_import_map_import_completions() {
           "sortText": "1",
           "insertText": ".",
           "commitCharacters": ["\"", "'"],
-        },
-        {
+        }, {
           "label": "..",
           "kind": 19,
           "detail": "(local)",
           "sortText": "1",
           "insertText": "..",
           "commitCharacters": ["\"", "'"],
-        },
-        {
+        }, {
           "label": "std",
           "kind": 19,
           "detail": "(import map)",
           "sortText": "std",
           "insertText": "std",
           "commitCharacters": ["\"", "'"],
-        },
-        {
+        }, {
           "label": "fs",
           "kind": 17,
           "detail": "(import map)",
           "sortText": "fs",
           "insertText": "fs",
           "commitCharacters": ["\"", "'"],
-        },
-        {
+        }, {
           "label": "/~",
           "kind": 19,
           "detail": "(import map)",
@@ -910,14 +830,8 @@ fn lsp_import_map_import_completions() {
         "contentChanges": [
           {
             "range": {
-              "start": {
-                "line": 1,
-                "character": 20
-              },
-              "end": {
-                "line": 1,
-                "character": 20
-              }
+              "start": { "line": 1, "character": 20 },
+              "end": { "line": 1, "character": 20 }
             },
             "text": "/~/"
           }
@@ -939,10 +853,7 @@ fn lsp_import_map_import_completions() {
         "textDocument": {
           "uri": uri
         },
-        "position": {
-          "line": 1,
-          "character": 23
-        },
+        "position": { "line": 1, "character": 23 },
         "context": {
           "triggerKind": 2,
           "triggerCharacter": "/"
@@ -964,14 +875,8 @@ fn lsp_import_map_import_completions() {
           "filterText": "/~/b.ts",
           "textEdit": {
             "range": {
-              "start": {
-                "line": 1,
-                "character": 20
-              },
-              "end": {
-                "line": 1,
-                "character": 23
-              }
+              "start": { "line": 1, "character": 20 },
+              "end": { "line": 1, "character": 23 }
             },
             "newText": "/~/b.ts"
           },
@@ -981,12 +886,13 @@ fn lsp_import_map_import_completions() {
     }))
   );
 
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_hover() {
-  let mut client = init("initialize_params.json");
+  let mut client = LspClientBuilder::new().build();
+  client.initialize_default();
   did_open(
     &mut client,
     json!({
@@ -1005,10 +911,7 @@ fn lsp_hover() {
         "textDocument": {
           "uri": "file:///a/file.ts"
         },
-        "position": {
-          "line": 0,
-          "character": 19
-        }
+        "position": { "line": 0, "character": 19 }
       }),
     )
     .unwrap();
@@ -1025,23 +928,18 @@ fn lsp_hover() {
         "\n\n*@category* - Runtime Environment",
       ],
       "range": {
-        "start": {
-          "line": 0,
-          "character": 17
-        },
-        "end": {
-          "line": 0,
-          "character": 21
-        }
+        "start": { "line": 0, "character": 17 },
+        "end": { "line": 0, "character": 21 }
       }
     }))
   );
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_hover_asset() {
-  let mut client = init("initialize_params.json");
+  let mut client = LspClientBuilder::new().build();
+  client.initialize_default();
   did_open(
     &mut client,
     json!({
@@ -1060,10 +958,7 @@ fn lsp_hover_asset() {
         "textDocument": {
           "uri": "file:///a/file.ts"
         },
-        "position": {
-          "line": 0,
-          "character": 14
-        }
+        "position": { "line": 0, "character": 14 }
       }),
     )
     .unwrap();
@@ -1086,10 +981,7 @@ fn lsp_hover_asset() {
         "textDocument": {
           "uri": "deno:/asset/lib.es2015.symbol.wellknown.d.ts"
         },
-        "position": {
-          "line": 109,
-          "character": 13
-        }
+        "position": { "line": 109, "character": 13 }
       }),
     )
     .unwrap();
@@ -1105,23 +997,21 @@ fn lsp_hover_asset() {
         "Enables basic storage and retrieval of dates and times."
       ],
       "range": {
-        "start": {
-          "line": 109,
-          "character": 10,
-        },
-        "end": {
-          "line": 109,
-          "character": 14,
-        }
+        "start": { "line": 109, "character": 10, },
+        "end": { "line": 109, "character": 14, }
       }
     }))
   );
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_hover_disabled() {
-  let mut client = init("initialize_params_disabled.json");
+  let context = TestContextBuilder::new().build();
+  let mut client = context.new_lsp_command().build();
+  client.initialize(|builder| {
+    builder.set_deno_enable(false);
+  });
   client
     .write_notification(
       "textDocument/didOpen",
@@ -1145,21 +1035,22 @@ fn lsp_hover_disabled() {
         "textDocument": {
           "uri": "file:///a/file.ts"
         },
-        "position": {
-          "line": 0,
-          "character": 19
-        }
+        "position": { "line": 0, "character": 19 }
       }),
     )
     .unwrap();
   assert!(maybe_err.is_none());
   assert_eq!(maybe_res, Some(json!(null)));
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_inlay_hints() {
-  let mut client = init("initialize_params_hints.json");
+  let context = TestContextBuilder::new().build();
+  let mut client = context.new_lsp_command().build();
+  client.initialize(|builder| {
+    builder.enable_inlay_hints();
+  });
   did_open(
     &mut client,
     json!({
@@ -1198,14 +1089,8 @@ fn lsp_inlay_hints() {
           "uri": "file:///a/file.ts",
         },
         "range": {
-          "start": {
-            "line": 0,
-            "character": 0
-          },
-          "end": {
-            "line": 19,
-            "character": 0,
-          }
+          "start": { "line": 0, "character": 0 },
+          "end": { "line": 19, "character": 0, }
         }
       }),
     )
@@ -1215,90 +1100,51 @@ fn lsp_inlay_hints() {
     json!(maybe_res),
     json!([
       {
-        "position": {
-          "line": 0,
-          "character": 21
-        },
+        "position": { "line": 0, "character": 21 },
         "label": ": string",
         "kind": 1,
         "paddingLeft": true
-      },
-      {
-        "position": {
-          "line": 4,
-          "character": 10
-        },
+      }, {
+        "position": { "line": 4, "character": 10 },
         "label": "b:",
         "kind": 2,
         "paddingRight": true
-      },
-      {
-        "position": {
-          "line": 7,
-          "character": 11
-        },
+      }, {
+        "position": { "line": 7, "character": 11 },
         "label": "= 0",
         "paddingLeft": true
-      },
-      {
-        "position": {
-          "line": 10,
-          "character": 17
-        },
+      }, {
+        "position": { "line": 10, "character": 17 },
         "label": "string:",
         "kind": 2,
         "paddingRight": true
-      },
-      {
-        "position": {
-          "line": 10,
-          "character": 24
-        },
+      }, {
+        "position": { "line": 10, "character": 24 },
         "label": "radix:",
         "kind": 2,
         "paddingRight": true
-      },
-      {
-        "position": {
-          "line": 12,
-          "character": 15
-        },
+      }, {
+        "position": { "line": 12, "character": 15 },
         "label": ": number",
         "kind": 1,
         "paddingLeft": true
-      },
-      {
-        "position": {
-          "line": 15,
-          "character": 11
-        },
+      }, {
+        "position": { "line": 15, "character": 11 },
         "label": ": number",
         "kind": 1,
         "paddingLeft": true
-      },
-      {
-        "position": {
-          "line": 18,
-          "character": 18
-        },
+      }, {
+        "position": { "line": 18, "character": 18 },
         "label": "callbackfn:",
         "kind": 2,
         "paddingRight": true
-      },
-      {
-        "position": {
-          "line": 18,
-          "character": 20
-        },
+      }, {
+        "position": { "line": 18, "character": 20 },
         "label": ": string",
         "kind": 1,
         "paddingLeft": true
-      },
-      {
-        "position": {
-          "line": 18,
-          "character": 21
-        },
+      }, {
+        "position": { "line": 18, "character": 21 },
         "label": ": string",
         "kind": 1,
         "paddingLeft": true
@@ -1309,7 +1155,8 @@ fn lsp_inlay_hints() {
 
 #[test]
 fn lsp_inlay_hints_not_enabled() {
-  let mut client = init("initialize_params.json");
+  let mut client = LspClientBuilder::new().build();
+  client.initialize_default();
   did_open(
     &mut client,
     json!({
@@ -1348,14 +1195,8 @@ fn lsp_inlay_hints_not_enabled() {
           "uri": "file:///a/file.ts",
         },
         "range": {
-          "start": {
-            "line": 0,
-            "character": 0
-          },
-          "end": {
-            "line": 19,
-            "character": 0,
-          }
+          "start": { "line": 0, "character": 0 },
+          "end": { "line": 19, "character": 0, }
         }
       }),
     )
@@ -1366,39 +1207,31 @@ fn lsp_inlay_hints_not_enabled() {
 
 #[test]
 fn lsp_workspace_enable_paths() {
-  let mut params: lsp::InitializeParams = serde_json::from_value(load_fixture(
-    "initialize_params_workspace_enable_paths.json",
-  ))
-  .unwrap();
+  let context = TestContextBuilder::new().build();
   // we aren't actually writing anything to the tempdir in this test, but we
   // just need a legitimate file path on the host system so that logic that
   // tries to convert to and from the fs paths works on all env
-  let temp_dir = TempDir::new();
-
-  let root_specifier =
-    ensure_directory_specifier(Url::from_file_path(temp_dir.path()).unwrap());
-
-  params.root_uri = Some(root_specifier.clone());
-  params.workspace_folders = Some(vec![lsp::WorkspaceFolder {
-    uri: root_specifier.clone(),
-    name: "project".to_string(),
-  }]);
-
-  let deno_exe = deno_exe_path();
-  let mut client = LspClient::new(&deno_exe, false).unwrap();
-  client
-    .write_request::<_, _, Value>("initialize", params)
-    .unwrap();
-
-  client.write_notification("initialized", json!({})).unwrap();
+  let temp_dir = context.deno_dir();
+
+  let root_specifier = temp_dir.uri();
+
+  let mut client = context.new_lsp_command().build();
+  client.initialize(|builder| {
+    builder
+      .set_enable_paths(vec!["./worker".to_string()])
+      .set_root_uri(root_specifier.clone())
+      .set_workspace_folders(vec![lsp::WorkspaceFolder {
+        uri: root_specifier.clone(),
+        name: "project".to_string(),
+      }])
+      .set_deno_enable(false);
+  });
 
   handle_configuration_request(
     &mut client,
     json!([{
       "enable": false,
-      "enablePaths": [
-        "./worker"
-      ],
+      "enablePaths": ["./worker"],
     }]),
   );
 
@@ -1457,10 +1290,7 @@ fn lsp_workspace_enable_paths() {
         "textDocument": {
           "uri": root_specifier.join("./file.ts").unwrap(),
         },
-        "position": {
-          "line": 0,
-          "character": 19
-        }
+        "position": { "line": 0, "character": 19 }
       }),
     )
     .unwrap();
@@ -1474,10 +1304,7 @@ fn lsp_workspace_enable_paths() {
         "textDocument": {
           "uri": root_specifier.join("./other/file.ts").unwrap(),
         },
-        "position": {
-          "line": 0,
-          "character": 19
-        }
+        "position": { "line": 0, "character": 19 }
       }),
     )
     .unwrap();
@@ -1491,10 +1318,7 @@ fn lsp_workspace_enable_paths() {
         "textDocument": {
           "uri": root_specifier.join("./worker/file.ts").unwrap(),
         },
-        "position": {
-          "line": 0,
-          "character": 19
-        }
+        "position": { "line": 0, "character": 19 }
       }),
     )
     .unwrap();
@@ -1510,14 +1334,8 @@ fn lsp_workspace_enable_paths() {
         "Returns the number of milliseconds elapsed since midnight, January 1, 1970 Universal Coordinated Time (UTC)."
       ],
       "range": {
-        "start": {
-          "line": 0,
-          "character": 17,
-        },
-        "end": {
-          "line": 0,
-          "character": 20,
-        }
+        "start": { "line": 0, "character": 17, },
+        "end": { "line": 0, "character": 20, }
       }
     }))
   );
@@ -1529,10 +1347,7 @@ fn lsp_workspace_enable_paths() {
         "textDocument": {
           "uri": root_specifier.join("./worker/subdir/file.ts").unwrap(),
         },
-        "position": {
-          "line": 0,
-          "character": 19
-        }
+        "position": { "line": 0, "character": 19 }
       }),
     )
     .unwrap();
@@ -1548,24 +1363,19 @@ fn lsp_workspace_enable_paths() {
         "Returns the number of milliseconds elapsed since midnight, January 1, 1970 Universal Coordinated Time (UTC)."
       ],
       "range": {
-        "start": {
-          "line": 0,
-          "character": 17,
-        },
-        "end": {
-          "line": 0,
-          "character": 20,
-        }
+        "start": { "line": 0, "character": 17, },
+        "end": { "line": 0, "character": 20, }
       }
     }))
   );
 
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_hover_unstable_disabled() {
-  let mut client = init("initialize_params.json");
+  let mut client = LspClientBuilder::new().build();
+  client.initialize_default();
   did_open(
     &mut client,
     json!({
@@ -1584,10 +1394,7 @@ fn lsp_hover_unstable_disabled() {
         "textDocument": {
           "uri": "file:///a/file.ts"
         },
-        "position": {
-          "line": 0,
-          "character": 19
-        }
+        "position": { "line": 0, "character": 19 }
       }),
     )
     .unwrap();
@@ -1602,23 +1409,20 @@ fn lsp_hover_unstable_disabled() {
         }
       ],
       "range": {
-        "start": {
-          "line": 0,
-          "character": 17
-        },
-        "end": {
-          "line": 0,
-          "character": 23
-        }
+        "start": { "line": 0, "character": 17 },
+        "end": { "line": 0, "character": 23 }
       }
     }))
   );
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_hover_unstable_enabled() {
-  let mut client = init("initialize_params_unstable.json");
+  let mut client = LspClientBuilder::new().build();
+  client.initialize(|builder| {
+    builder.set_unstable(true);
+  });
   did_open(
     &mut client,
     json!({
@@ -1637,10 +1441,7 @@ fn lsp_hover_unstable_enabled() {
         "textDocument": {
           "uri": "file:///a/file.ts"
         },
-        "position": {
-          "line": 0,
-          "character": 19
-        }
+        "position": { "line": 0, "character": 19 }
       }),
     )
     .unwrap();
@@ -1657,23 +1458,18 @@ fn lsp_hover_unstable_enabled() {
         "\n\n*@category* - Runtime Environment",
       ],
       "range":{
-        "start":{
-          "line":0,
-          "character":17
-        },
-        "end":{
-          "line":0,
-          "character":21
-        }
+        "start":{ "line":0, "character":17 },
+        "end":{ "line":0, "character":21 }
       }
     }))
   );
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_hover_change_mbc() {
-  let mut client = init("initialize_params.json");
+  let mut client = LspClientBuilder::new().build();
+  client.initialize_default();
   did_open(
     &mut client,
     json!({
@@ -1696,10 +1492,7 @@ fn lsp_hover_change_mbc() {
         "contentChanges": [
           {
             "range": {
-              "start": {
-                "line": 1,
-                "character": 11
-              },
+              "start": { "line": 1, "character": 11 },
               "end": {
                 "line": 1,
                 // the LSP uses utf16 encoded characters indexes, so
@@ -1726,10 +1519,7 @@ fn lsp_hover_change_mbc() {
         "textDocument": {
           "uri": "file:///a/file.ts"
         },
-        "position": {
-          "line": 2,
-          "character": 15
-        }
+        "position": { "line": 2, "character": 15 }
       }),
     )
     .unwrap();
@@ -1745,35 +1535,27 @@ fn lsp_hover_change_mbc() {
         "",
       ],
       "range": {
-        "start": {
-          "line": 2,
-          "character": 15,
-        },
-        "end": {
-          "line": 2,
-          "character": 16,
-        },
+        "start": { "line": 2, "character": 15, },
+        "end": { "line": 2, "character": 16, },
       }
     }))
   );
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_hover_closed_document() {
-  let temp_dir_guard = TempDir::new();
-  let temp_dir = temp_dir_guard.path();
-  let a_path = temp_dir.join("a.ts");
-  fs::write(a_path, r#"export const a = "a";"#).unwrap();
-  let b_path = temp_dir.join("b.ts");
-  fs::write(&b_path, r#"export * from "./a.ts";"#).unwrap();
-  let b_specifier = Url::from_file_path(b_path).unwrap();
-  let c_path = temp_dir.join("c.ts");
-  fs::write(&c_path, "import { a } from \"./b.ts\";\nconsole.log(a);\n")
-    .unwrap();
-  let c_specifier = Url::from_file_path(c_path).unwrap();
-
-  let mut client = init("initialize_params.json");
+  let context = TestContextBuilder::new().build();
+  let temp_dir = context.deno_dir();
+  temp_dir.write("a.ts", r#"export const a = "a";"#);
+  temp_dir.write("b.ts", r#"export * from "./a.ts";"#);
+  temp_dir.write("c.ts", "import { a } from \"./b.ts\";\nconsole.log(a);\n");
+
+  let b_specifier = temp_dir.uri().join("b.ts").unwrap();
+  let c_specifier = temp_dir.uri().join("c.ts").unwrap();
+
+  let mut client = context.new_lsp_command().build();
+  client.initialize_default();
   client
     .write_notification(
       "textDocument/didOpen",
@@ -1825,10 +1607,7 @@ fn lsp_hover_closed_document() {
         "textDocument": {
           "uri": c_specifier,
         },
-        "position": {
-          "line": 0,
-          "character": 10
-        }
+        "position": { "line": 0, "character": 10 }
       }),
     )
     .unwrap();
@@ -1844,14 +1623,8 @@ fn lsp_hover_closed_document() {
         ""
       ],
       "range": {
-        "start": {
-          "line": 0,
-          "character": 9
-        },
-        "end": {
-          "line": 0,
-          "character": 10
-        }
+        "start": { "line": 0, "character": 9 },
+        "end": { "line": 0, "character": 10 }
       }
     }))
   );
@@ -1872,10 +1645,7 @@ fn lsp_hover_closed_document() {
         "textDocument": {
           "uri": c_specifier,
         },
-        "position": {
-          "line": 0,
-          "character": 10
-        }
+        "position": { "line": 0, "character": 10 }
       }),
     )
     .unwrap();
@@ -1891,24 +1661,19 @@ fn lsp_hover_closed_document() {
         ""
       ],
       "range": {
-        "start": {
-          "line": 0,
-          "character": 9
-        },
-        "end": {
-          "line": 0,
-          "character": 10
-        }
+        "start": { "line": 0, "character": 9 },
+        "end": { "line": 0, "character": 10 }
       }
     }))
   );
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_hover_dependency() {
-  let _g = http_server();
-  let mut client = init("initialize_params.json");
+  let context = TestContextBuilder::new().use_http_server().build();
+  let mut client = context.new_lsp_command().build();
+  client.initialize_default();
   did_open(
     &mut client,
     json!({
@@ -1922,7 +1687,14 @@ fn lsp_hover_dependency() {
   );
   did_open(
     &mut client,
-    load_fixture("did_open_params_import_hover.json"),
+    json!({
+      "textDocument": {
+        "uri": "file:///a/file.ts",
+        "languageId": "typescript",
+        "version": 1,
+        "text": "import * as a from \"http://127.0.0.1:4545/xTypeScriptTypes.js\";\n// @deno-types=\"http://127.0.0.1:4545/type_definitions/foo.d.ts\"\nimport * as b from \"http://127.0.0.1:4545/type_definitions/foo.js\";\nimport * as c from \"http://127.0.0.1:4545/subdir/type_reference.js\";\nimport * as d from \"http://127.0.0.1:4545/subdir/mod1.ts\";\nimport * as e from \"data:application/typescript;base64,ZXhwb3J0IGNvbnN0IGEgPSAiYSI7CgpleHBvcnQgZW51bSBBIHsKICBBLAogIEIsCiAgQywKfQo=\";\nimport * as f from \"./file_01.ts\";\nimport * as g from \"http://localhost:4545/x/a/mod.ts\";\n\nconsole.log(a, b, c, d, e, f, g);\n"
+      }
+    }),
   );
   let (maybe_res, maybe_err) = client
     .write_request::<_, _, Value>(
@@ -1944,10 +1716,7 @@ fn lsp_hover_dependency() {
         "textDocument": {
           "uri": "file:///a/file.ts",
         },
-        "position": {
-          "line": 0,
-          "character": 28
-        }
+        "position": { "line": 0, "character": 28 }
       }),
     )
     .unwrap();
@@ -1960,14 +1729,8 @@ fn lsp_hover_dependency() {
         "value": "**Resolved Dependency**\n\n**Code**: http&#8203;://127.0.0.1:4545/xTypeScriptTypes.js\n\n**Types**: http&#8203;://127.0.0.1:4545/xTypeScriptTypes.d.ts\n"
       },
       "range": {
-        "start": {
-          "line": 0,
-          "character": 19
-        },
-        "end":{
-          "line": 0,
-          "character": 62
-        }
+        "start": { "line": 0, "character": 19 },
+        "end":{ "line": 0, "character": 62 }
       }
     }))
   );
@@ -1978,10 +1741,7 @@ fn lsp_hover_dependency() {
         "textDocument": {
           "uri": "file:///a/file.ts",
         },
-        "position": {
-          "line": 3,
-          "character": 28
-        }
+        "position": { "line": 3, "character": 28 }
       }),
     )
     .unwrap();
@@ -1994,14 +1754,8 @@ fn lsp_hover_dependency() {
         "value": "**Resolved Dependency**\n\n**Code**: http&#8203;://127.0.0.1:4545/subdir/type_reference.js\n\n**Types**: http&#8203;://127.0.0.1:4545/subdir/type_reference.d.ts\n"
       },
       "range": {
-        "start": {
-          "line": 3,
-          "character": 19
-        },
-        "end":{
-          "line": 3,
-          "character": 67
-        }
+        "start": { "line": 3, "character": 19 },
+        "end":{ "line": 3, "character": 67 }
       }
     }))
   );
@@ -2012,10 +1766,7 @@ fn lsp_hover_dependency() {
         "textDocument": {
           "uri": "file:///a/file.ts",
         },
-        "position": {
-          "line": 4,
-          "character": 28
-        }
+        "position": { "line": 4, "character": 28 }
       }),
     )
     .unwrap();
@@ -2028,14 +1779,8 @@ fn lsp_hover_dependency() {
         "value": "**Resolved Dependency**\n\n**Code**: http&#8203;://127.0.0.1:4545/subdir/mod1.ts\n"
       },
       "range": {
-        "start": {
-          "line": 4,
-          "character": 19
-        },
-        "end":{
-          "line": 4,
-          "character": 57
-        }
+        "start": { "line": 4, "character": 19 },
+        "end":{ "line": 4, "character": 57 }
       }
     }))
   );
@@ -2046,10 +1791,7 @@ fn lsp_hover_dependency() {
         "textDocument": {
           "uri": "file:///a/file.ts",
         },
-        "position": {
-          "line": 5,
-          "character": 28
-        }
+        "position": { "line": 5, "character": 28 }
       }),
     )
     .unwrap();
@@ -2062,14 +1804,8 @@ fn lsp_hover_dependency() {
         "value": "**Resolved Dependency**\n\n**Code**: _(a data url)_\n"
       },
       "range": {
-        "start": {
-          "line": 5,
-          "character": 19
-        },
-        "end":{
-          "line": 5,
-          "character": 132
-        }
+        "start": { "line": 5, "character": 19 },
+        "end":{ "line": 5, "character": 132 }
       }
     }))
   );
@@ -2080,10 +1816,7 @@ fn lsp_hover_dependency() {
         "textDocument": {
           "uri": "file:///a/file.ts",
         },
-        "position": {
-          "line": 6,
-          "character": 28
-        }
+        "position": { "line": 6, "character": 28 }
       }),
     )
     .unwrap();
@@ -2096,14 +1829,8 @@ fn lsp_hover_dependency() {
         "value": "**Resolved Dependency**\n\n**Code**: file&#8203;:///a/file_01.ts\n"
       },
       "range": {
-        "start": {
-          "line": 6,
-          "character": 19
-        },
-        "end":{
-          "line": 6,
-          "character": 33
-        }
+        "start": { "line": 6, "character": 19 },
+        "end":{ "line": 6, "character": 33 }
       }
     }))
   );
@@ -2113,7 +1840,8 @@ fn lsp_hover_dependency() {
 // unable to resolve dependencies when there was an invalid syntax in the module
 #[test]
 fn lsp_hover_deps_preserved_when_invalid_parse() {
-  let mut client = init("initialize_params.json");
+  let mut client = LspClientBuilder::new().build();
+  client.initialize_default();
   did_open(
     &mut client,
     json!({
@@ -2143,10 +1871,7 @@ fn lsp_hover_deps_preserved_when_invalid_parse() {
         "textDocument": {
           "uri": "file:///a/file2.ts"
         },
-        "position": {
-          "line": 0,
-          "character": 56
-        }
+        "position": { "line": 0, "character": 56 }
       }),
     )
     .unwrap();
@@ -2162,14 +1887,8 @@ fn lsp_hover_deps_preserved_when_invalid_parse() {
         ""
       ],
       "range": {
-        "start": {
-          "line": 0,
-          "character": 56,
-        },
-        "end": {
-          "line": 0,
-          "character": 57,
-        }
+        "start": { "line": 0, "character": 56, },
+        "end": { "line": 0, "character": 57, }
       }
     }))
   );
@@ -2184,14 +1903,8 @@ fn lsp_hover_deps_preserved_when_invalid_parse() {
         "contentChanges": [
           {
             "range": {
-              "start": {
-                "line": 0,
-                "character": 57
-              },
-              "end": {
-                "line": 0,
-                "character": 58
-              }
+              "start": { "line": 0, "character": 57 },
+              "end": { "line": 0, "character": 58 }
             },
             "text": "."
           }
@@ -2206,10 +1919,7 @@ fn lsp_hover_deps_preserved_when_invalid_parse() {
         "textDocument": {
           "uri": "file:///a/file2.ts"
         },
-        "position": {
-          "line": 0,
-          "character": 56
-        }
+        "position": { "line": 0, "character": 56 }
       }),
     )
     .unwrap();
@@ -2225,24 +1935,19 @@ fn lsp_hover_deps_preserved_when_invalid_parse() {
         ""
       ],
       "range": {
-        "start": {
-          "line": 0,
-          "character": 56,
-        },
-        "end": {
-          "line": 0,
-          "character": 57,
-        }
+        "start": { "line": 0, "character": 56, },
+        "end": { "line": 0, "character": 57, }
       }
     }))
   );
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_hover_typescript_types() {
-  let _g = http_server();
-  let mut client = init("initialize_params.json");
+  let context = TestContextBuilder::new().use_http_server().build();
+  let mut client = context.new_lsp_command().build();
+  client.initialize_default();
   did_open(
     &mut client,
     json!({
@@ -2278,10 +1983,7 @@ fn lsp_hover_typescript_types() {
         "textDocument": {
           "uri": "file:///a/file.ts"
         },
-        "position": {
-          "line": 0,
-          "character": 24
-        }
+        "position": { "line": 0, "character": 24 }
       }),
     )
     .unwrap();
@@ -2295,23 +1997,18 @@ fn lsp_hover_typescript_types() {
         "value": "**Resolved Dependency**\n\n**Code**: http&#8203;://127.0.0.1:4545/xTypeScriptTypes.js\n\n**Types**: http&#8203;://127.0.0.1:4545/xTypeScriptTypes.d.ts\n"
       },
       "range": {
-        "start": {
-          "line": 0,
-          "character": 19
-        },
-        "end": {
-          "line": 0,
-          "character": 62
-        }
+        "start": { "line": 0, "character": 19 },
+        "end": { "line": 0, "character": 62 }
       }
     })
   );
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_hover_jsdoc_symbol_link() {
-  let mut client = init("initialize_params.json");
+  let mut client = LspClientBuilder::new().build();
+  client.initialize_default();
   did_open(
     &mut client,
     json!({
@@ -2341,10 +2038,7 @@ fn lsp_hover_jsdoc_symbol_link() {
         "textDocument": {
           "uri": "file:///a/file.ts"
         },
-        "position": {
-          "line": 7,
-          "character": 10
-        }
+        "position": { "line": 7, "character": 10 }
       }),
     )
     .unwrap();
@@ -2360,23 +2054,18 @@ fn lsp_hover_jsdoc_symbol_link() {
         "JSDoc [hello](file:///a/file.ts#L1,10) and [`b`](file:///a/file.ts#L5,7)"
       ],
       "range": {
-        "start": {
-          "line": 7,
-          "character": 9
-        },
-        "end": {
-          "line": 7,
-          "character": 10
-        }
+        "start": { "line": 7, "character": 9 },
+        "end": { "line": 7, "character": 10 }
       }
     }))
   );
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_goto_type_definition() {
-  let mut client = init("initialize_params.json");
+  let mut client = LspClientBuilder::new().build();
+  client.initialize_default();
   did_open(
     &mut client,
     json!({
@@ -2395,10 +2084,7 @@ fn lsp_goto_type_definition() {
         "textDocument": {
           "uri": "file:///a/file.ts"
         },
-        "position": {
-          "line": 12,
-          "character": 1
-        }
+        "position": { "line": 12, "character": 1 }
       }),
     )
     .unwrap();
@@ -2409,34 +2095,23 @@ fn lsp_goto_type_definition() {
       {
         "targetUri": "file:///a/file.ts",
         "targetRange": {
-          "start": {
-            "line": 4,
-            "character": 0
-          },
-          "end": {
-            "line": 9,
-            "character": 1
-          }
+          "start": { "line": 4, "character": 0 },
+          "end": { "line": 9, "character": 1 }
         },
         "targetSelectionRange": {
-          "start": {
-            "line": 4,
-            "character": 13
-          },
-          "end": {
-            "line": 4,
-            "character": 14
-          }
+          "start": { "line": 4, "character": 13 },
+          "end": { "line": 4, "character": 14 }
         }
       }
     ]))
   );
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_call_hierarchy() {
-  let mut client = init("initialize_params.json");
+  let mut client = LspClientBuilder::new().build();
+  client.initialize_default();
   did_open(
     &mut client,
     json!({
@@ -2455,47 +2130,141 @@ fn lsp_call_hierarchy() {
         "textDocument": {
           "uri": "file:///a/file.ts"
         },
-        "position": {
-          "line": 5,
-          "character": 3
-        }
+        "position": { "line": 5, "character": 3 }
       }),
     )
     .unwrap();
   assert!(maybe_error.is_none());
   assert_eq!(
     maybe_res,
-    Some(load_fixture("prepare_call_hierarchy_response.json"))
-  );
+    Some(json!([{
+      "name": "baz",
+      "kind": 6,
+      "detail": "Bar",
+      "uri": "file:///a/file.ts",
+      "range": {
+        "start": { "line": 5, "character": 2 },
+        "end": { "line": 7, "character": 3 }
+      },
+      "selectionRange": {
+        "start": { "line": 5, "character": 2 },
+        "end": { "line": 5, "character": 5 }
+      }
+    }]))
+  );
   let (maybe_res, maybe_error) = client
     .write_request(
       "callHierarchy/incomingCalls",
-      load_fixture("incoming_calls_params.json"),
+      json!({
+        "item": {
+          "name": "baz",
+          "kind": 6,
+          "detail": "Bar",
+          "uri": "file:///a/file.ts",
+          "range": {
+            "start": { "line": 5, "character": 2 },
+            "end": { "line": 7, "character": 3 }
+          },
+          "selectionRange": {
+            "start": { "line": 5, "character": 2 },
+            "end": { "line": 5, "character": 5 }
+          }
+        }
+      }),
     )
     .unwrap();
   assert!(maybe_error.is_none());
   assert_eq!(
     maybe_res,
-    Some(load_fixture("incoming_calls_response.json"))
+    Some(json!([{
+      "from": {
+        "name": "main",
+        "kind": 12,
+        "detail": "",
+        "uri": "file:///a/file.ts",
+        "range": {
+          "start": { "line": 10, "character": 0 },
+          "end": { "line": 13, "character": 1 }
+        },
+        "selectionRange": {
+          "start": { "line": 10, "character": 9 },
+          "end": { "line": 10, "character": 13 }
+        }
+      },
+      "fromRanges": [
+        {
+          "start": { "line": 12, "character": 6 },
+          "end": { "line": 12, "character": 9 }
+        }
+      ]
+    }]))
   );
   let (maybe_res, maybe_error) = client
     .write_request(
       "callHierarchy/outgoingCalls",
-      load_fixture("outgoing_calls_params.json"),
+      json!({
+        "item": {
+          "name": "baz",
+          "kind": 6,
+          "detail": "Bar",
+          "uri": "file:///a/file.ts",
+          "range": {
+            "start": { "line": 5, "character": 2 },
+            "end": { "line": 7, "character": 3 }
+          },
+          "selectionRange": {
+            "start": { "line": 5, "character": 2 },
+            "end": { "line": 5, "character": 5 }
+          }
+        }
+      }),
     )
     .unwrap();
   assert!(maybe_error.is_none());
   assert_eq!(
     maybe_res,
-    Some(load_fixture("outgoing_calls_response.json"))
+    Some(json!([{
+      "to": {
+        "name": "foo",
+        "kind": 12,
+        "detail": "",
+        "uri": "file:///a/file.ts",
+        "range": {
+          "start": { "line": 0, "character": 0 },
+          "end": { "line": 2, "character": 1 }
+        },
+        "selectionRange": {
+          "start": { "line": 0, "character": 9 },
+          "end": { "line": 0, "character": 12 }
+        }
+      },
+      "fromRanges": [{
+        "start": { "line": 6, "character": 11 },
+        "end": { "line": 6, "character": 14 }
+      }]
+    }]))
   );
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_large_doc_changes() {
-  let mut client = init("initialize_params.json");
-  did_open(&mut client, load_fixture("did_open_params_large.json"));
+  let mut client = LspClientBuilder::new().build();
+  client.initialize_default();
+  let large_file_text =
+    fs::read_to_string(testdata_path().join("lsp").join("large_file.txt"))
+      .unwrap();
+  did_open(
+    &mut client,
+    json!({
+      "textDocument": {
+        "uri": "file:///a/file.ts",
+        "languageId": "javascript",
+        "version": 1,
+        "text": large_file_text,
+      }
+    }),
+  );
   client
     .write_notification(
       "textDocument/didChange",
@@ -2507,14 +2276,8 @@ fn lsp_large_doc_changes() {
         "contentChanges": [
           {
             "range": {
-              "start": {
-                "line": 444,
-                "character": 11
-              },
-              "end": {
-                "line": 444,
-                "character": 14
-              }
+              "start": { "line": 444, "character": 11 },
+              "end": { "line": 444, "character": 14 }
             },
             "text": "+++"
           }
@@ -2533,14 +2296,8 @@ fn lsp_large_doc_changes() {
         "contentChanges": [
           {
             "range": {
-              "start": {
-                "line": 445,
-                "character": 4
-              },
-              "end": {
-                "line": 445,
-                "character": 4
-              }
+              "start": { "line": 445, "character": 4 },
+              "end": { "line": 445, "character": 4 }
             },
             "text": "// "
           }
@@ -2559,14 +2316,8 @@ fn lsp_large_doc_changes() {
         "contentChanges": [
           {
             "range": {
-              "start": {
-                "line": 477,
-                "character": 4
-              },
-              "end": {
-                "line": 477,
-                "character": 9
-              }
+              "start": { "line": 477, "character": 4 },
+              "end": { "line": 477, "character": 9 }
             },
             "text": "error"
           }
@@ -2581,10 +2332,7 @@ fn lsp_large_doc_changes() {
         "textDocument": {
           "uri": "file:///a/file.ts"
         },
-        "position": {
-          "line": 421,
-          "character": 30
-        }
+        "position": { "line": 421, "character": 30 }
       }),
     )
     .unwrap();
@@ -2597,10 +2345,7 @@ fn lsp_large_doc_changes() {
         "textDocument": {
           "uri": "file:///a/file.ts"
         },
-        "position": {
-          "line": 444,
-          "character": 6
-        }
+        "position": { "line": 444, "character": 6 }
       }),
     )
     .unwrap();
@@ -2613,24 +2358,32 @@ fn lsp_large_doc_changes() {
         "textDocument": {
           "uri": "file:///a/file.ts"
         },
-        "position": {
-          "line": 461,
-          "character": 34
-        }
+        "position": { "line": 461, "character": 34 }
       }),
     )
     .unwrap();
   assert!(maybe_res.is_some());
   assert!(maybe_err.is_none());
-  shutdown(&mut client);
+  client.shutdown();
 
   assert!(client.duration().as_millis() <= 15000);
 }
 
 #[test]
 fn lsp_document_symbol() {
-  let mut client = init("initialize_params.json");
-  did_open(&mut client, load_fixture("did_open_params_doc_symbol.json"));
+  let mut client = LspClientBuilder::new().build();
+  client.initialize_default();
+  did_open(
+    &mut client,
+    json!({
+      "textDocument": {
+        "uri": "file:///a/file.ts",
+        "languageId": "typescript",
+        "version": 1,
+        "text": "interface IFoo {\n  foo(): boolean;\n}\n\nclass Bar implements IFoo {\n  constructor(public x: number) { }\n  foo() { return true; }\n  /** @deprecated */\n  baz() { return false; }\n  get value(): number { return 0; }\n  set value(newVavlue: number) { return; }\n  static staticBar = new Bar(0);\n  private static getStaticBar() { return Bar.staticBar; }\n}\n\nenum Values { value1, value2 }\n\nvar bar: IFoo = new Bar(3);"
+      }
+    }),
+  );
   let (maybe_res, maybe_err) = client
     .write_request(
       "textDocument/documentSymbol",
@@ -2644,14 +2397,185 @@ fn lsp_document_symbol() {
   assert!(maybe_err.is_none());
   assert_eq!(
     maybe_res,
-    Some(load_fixture("document_symbol_response.json"))
+    Some(json!([{
+      "name": "bar",
+      "kind": 13,
+      "range": {
+        "start": { "line": 17, "character": 4 },
+        "end": { "line": 17, "character": 26 }
+      },
+      "selectionRange": {
+        "start": { "line": 17, "character": 4 },
+        "end": { "line": 17, "character": 7 }
+      }
+    }, {
+      "name": "Bar",
+      "kind": 5,
+      "range": {
+        "start": { "line": 4, "character": 0 },
+        "end": { "line": 13, "character": 1 }
+      },
+      "selectionRange": {
+        "start": { "line": 4, "character": 6 },
+        "end": { "line": 4, "character": 9 }
+      },
+      "children": [{
+        "name": "constructor",
+        "kind": 9,
+        "range": {
+          "start": { "line": 5, "character": 2 },
+          "end": { "line": 5, "character": 35 }
+        },
+        "selectionRange": {
+          "start": { "line": 5, "character": 2 },
+          "end": { "line": 5, "character": 35 }
+        }
+      }, {
+        "name": "baz",
+        "kind": 6,
+        "tags": [1],
+        "range": {
+          "start": { "line": 8, "character": 2 },
+          "end": { "line": 8, "character": 25 }
+        },
+        "selectionRange": {
+          "start": { "line": 8, "character": 2 },
+          "end": { "line": 8, "character": 5 }
+        }
+      }, {
+        "name": "foo",
+        "kind": 6,
+        "range": {
+          "start": { "line": 6, "character": 2 },
+          "end": { "line": 6, "character": 24 }
+        },
+        "selectionRange": {
+          "start": { "line": 6, "character": 2 },
+          "end": { "line": 6, "character": 5 }
+        }
+      }, {
+        "name": "getStaticBar",
+        "kind": 6,
+        "range": {
+          "start": { "line": 12, "character": 2 },
+          "end": { "line": 12, "character": 57 }
+        },
+        "selectionRange": {
+          "start": { "line": 12, "character": 17 },
+          "end": { "line": 12, "character": 29 }
+        }
+      }, {
+        "name": "staticBar",
+        "kind": 8,
+        "range": {
+          "start": { "line": 11, "character": 2 },
+          "end": { "line": 11, "character": 32 }
+        },
+        "selectionRange": {
+          "start": { "line": 11, "character": 9 },
+          "end": { "line": 11, "character": 18 }
+        }
+      }, {
+        "name": "(get) value",
+        "kind": 8,
+        "range": {
+          "start": { "line": 9, "character": 2 },
+          "end": { "line": 9, "character": 35 }
+        },
+        "selectionRange": {
+          "start": { "line": 9, "character": 6 },
+          "end": { "line": 9, "character": 11 }
+        }
+      }, {
+        "name": "(set) value",
+        "kind": 8,
+        "range": {
+          "start": { "line": 10, "character": 2 },
+          "end": { "line": 10, "character": 42 }
+        },
+        "selectionRange": {
+          "start": { "line": 10, "character": 6 },
+          "end": { "line": 10, "character": 11 }
+        }
+      }, {
+        "name": "x",
+        "kind": 8,
+        "range": {
+          "start": { "line": 5, "character": 14 },
+          "end": { "line": 5, "character": 30 }
+        },
+        "selectionRange": {
+          "start": { "line": 5, "character": 21 },
+          "end": { "line": 5, "character": 22 }
+        }
+      }]
+    }, {
+      "name": "IFoo",
+      "kind": 11,
+      "range": {
+        "start": { "line": 0, "character": 0 },
+        "end": { "line": 2, "character": 1 }
+      },
+      "selectionRange": {
+        "start": { "line": 0, "character": 10 },
+        "end": { "line": 0, "character": 14 }
+      },
+      "children": [{
+        "name": "foo",
+        "kind": 6,
+        "range": {
+          "start": { "line": 1, "character": 2 },
+          "end": { "line": 1, "character": 17 }
+        },
+        "selectionRange": {
+          "start": { "line": 1, "character": 2 },
+          "end": { "line": 1, "character": 5 }
+        }
+      }]
+    }, {
+      "name": "Values",
+      "kind": 10,
+      "range": {
+        "start": { "line": 15, "character": 0 },
+        "end": { "line": 15, "character": 30 }
+      },
+      "selectionRange": {
+        "start": { "line": 15, "character": 5 },
+        "end": { "line": 15, "character": 11 }
+      },
+      "children": [{
+        "name": "value1",
+        "kind": 22,
+        "range": {
+          "start": { "line": 15, "character": 14 },
+          "end": { "line": 15, "character": 20 }
+        },
+        "selectionRange": {
+          "start": { "line": 15, "character": 14 },
+          "end": { "line": 15, "character": 20 }
+        }
+      }, {
+        "name": "value2",
+        "kind": 22,
+        "range": {
+          "start": { "line": 15, "character": 22 },
+          "end": { "line": 15, "character": 28 }
+        },
+        "selectionRange": {
+          "start": { "line": 15, "character": 22 },
+          "end": { "line": 15, "character": 28 }
+        }
+      }]
+    }]
+    ))
   );
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_folding_range() {
-  let mut client = init("initialize_params.json");
+  let mut client = LspClientBuilder::new().build();
+  client.initialize_default();
   did_open(
     &mut client,
     json!({
@@ -2676,37 +2600,32 @@ fn lsp_folding_range() {
   assert!(maybe_err.is_none());
   assert_eq!(
     maybe_res,
-    Some(json!([
-      {
-        "startLine": 0,
-        "endLine": 12,
-        "kind": "region"
-      },
-      {
-        "startLine": 1,
-        "endLine": 3,
-        "kind": "comment"
-      },
-      {
-        "startLine": 4,
-        "endLine": 10
-      },
-      {
-        "startLine": 5,
-        "endLine": 9
-      },
-      {
-        "startLine": 6,
-        "endLine": 7
-      }
-    ]))
+    Some(json!([{
+      "startLine": 0,
+      "endLine": 12,
+      "kind": "region"
+    }, {
+      "startLine": 1,
+      "endLine": 3,
+      "kind": "comment"
+    }, {
+      "startLine": 4,
+      "endLine": 10
+    }, {
+      "startLine": 5,
+      "endLine": 9
+    }, {
+      "startLine": 6,
+      "endLine": 7
+    }]))
   );
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_rename() {
-  let mut client = init("initialize_params.json");
+  let mut client = LspClientBuilder::new().build();
+  client.initialize_default();
   did_open(
     &mut client,
     json!({
@@ -2726,22 +2645,43 @@ fn lsp_rename() {
         "textDocument": {
           "uri": "file:///a/file.ts"
         },
-        "position": {
-          "line": 0,
-          "character": 4
-        },
+        "position": { "line": 0, "character": 4 },
         "newName": "variable_modified"
       }),
     )
     .unwrap();
   assert!(maybe_err.is_none());
-  assert_eq!(maybe_res, Some(load_fixture("rename_response.json")));
-  shutdown(&mut client);
+  assert_eq!(
+    maybe_res,
+    Some(json!({
+      "documentChanges": [{
+        "textDocument": {
+          "uri": "file:///a/file.ts",
+          "version": 1
+        },
+        "edits": [{
+          "range": {
+            "start": { "line": 0, "character": 4 },
+            "end": { "line": 0, "character": 12 }
+          },
+          "newText": "variable_modified"
+        }, {
+          "range": {
+            "start": { "line": 1, "character": 12 },
+            "end": { "line": 1, "character": 20 }
+          },
+          "newText": "variable_modified"
+        }]
+      }]
+    }))
+  );
+  client.shutdown();
 }
 
 #[test]
 fn lsp_selection_range() {
-  let mut client = init("initialize_params.json");
+  let mut client = LspClientBuilder::new().build();
+  client.initialize_default();
   did_open(
     &mut client,
     json!({
@@ -2760,29 +2700,79 @@ fn lsp_selection_range() {
         "textDocument": {
           "uri": "file:///a/file.ts"
         },
-        "positions": [
-          {
-            "line": 2,
-            "character": 8
-          }
-        ]
+        "positions": [{ "line": 2, "character": 8 }]
       }),
     )
     .unwrap();
   assert!(maybe_err.is_none());
   assert_eq!(
     maybe_res,
-    Some(load_fixture("selection_range_response.json"))
+    Some(json!([{
+      "range": {
+        "start": { "line": 2, "character": 8 },
+        "end": { "line": 2, "character": 9 }
+      },
+      "parent": {
+        "range": {
+          "start": { "line": 2, "character": 8 },
+          "end": { "line": 2, "character": 15 }
+        },
+        "parent": {
+          "range": {
+            "start": { "line": 2, "character": 4 },
+            "end": { "line": 4, "character": 5 }
+          },
+          "parent": {
+            "range": {
+              "start": { "line": 1, "character": 13 },
+              "end": { "line": 6, "character": 2 }
+            },
+            "parent": {
+              "range": {
+                "start": { "line": 1, "character": 12 },
+                "end": { "line": 6, "character": 3 }
+              },
+              "parent": {
+                "range": {
+                  "start": { "line": 1, "character": 2 },
+                  "end": { "line": 6, "character": 3 }
+                },
+                "parent": {
+                  "range": {
+                    "start": { "line": 0, "character": 11 },
+                    "end": { "line": 7, "character": 0 }
+                  },
+                  "parent": {
+                    "range": {
+                      "start": { "line": 0, "character": 0 },
+                      "end": { "line": 7, "character": 1 }
+                    }
+                  }
+                }
+              }
+            }
+          }
+        }
+      }
+    }]))
   );
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_semantic_tokens() {
-  let mut client = init("initialize_params.json");
+  let mut client = LspClientBuilder::new().build();
+  client.initialize_default();
   did_open(
     &mut client,
-    load_fixture("did_open_params_semantic_tokens.json"),
+    json!({
+      "textDocument": {
+        "uri": "file:///a/file.ts",
+        "languageId": "typescript",
+        "version": 1,
+        "text": "enum Values { value1, value2 }\n\nasync function baz(s: string): Promise<string> {\n  const r = s.slice(0);\n  return r;\n}\n\ninterface IFoo {\n  readonly x: number;\n  foo(): boolean;\n}\n\nclass Bar implements IFoo {\n  constructor(public readonly x: number) { }\n  foo() { return true; }\n  static staticBar = new Bar(0);\n  private static getStaticBar() { return Bar.staticBar; }\n}\n"
+      }
+    }),
   );
   let (maybe_res, maybe_err) = client
     .write_request(
@@ -2815,14 +2805,8 @@ fn lsp_semantic_tokens() {
           "uri": "file:///a/file.ts"
         },
         "range": {
-          "start": {
-            "line": 0,
-            "character": 0
-          },
-          "end": {
-            "line": 6,
-            "character": 0
-          }
+          "start": { "line": 0, "character": 0 },
+          "end": { "line": 6, "character": 0 }
         }
       }),
     )
@@ -2838,12 +2822,13 @@ fn lsp_semantic_tokens() {
       ]
     }))
   );
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_code_lens() {
-  let mut client = init("initialize_params.json");
+  let mut client = LspClientBuilder::new().build();
+  client.initialize_default();
   did_open(
     &mut client,
     json!({
@@ -2866,20 +2851,35 @@ fn lsp_code_lens() {
     )
     .unwrap();
   assert!(maybe_err.is_none());
-  assert_eq!(maybe_res, Some(load_fixture("code_lens_response.json")));
+  assert_eq!(
+    maybe_res,
+    Some(json!([{
+      "range": {
+        "start": { "line": 0, "character": 6 },
+        "end": { "line": 0, "character": 7 }
+      },
+      "data": {
+        "specifier": "file:///a/file.ts",
+        "source": "references"
+      }
+    }, {
+      "range": {
+        "start": { "line": 1, "character": 2 },
+        "end": { "line": 1, "character": 3 }
+      },
+      "data": {
+        "specifier": "file:///a/file.ts",
+        "source": "references"
+      }
+    }]))
+  );
   let (maybe_res, maybe_err) = client
     .write_request(
       "codeLens/resolve",
       json!({
         "range": {
-          "start": {
-            "line": 0,
-            "character": 6
-          },
-          "end": {
-            "line": 0,
-            "character": 7
-          }
+          "start": { "line": 0, "character": 6 },
+          "end": { "line": 0, "character": 7 }
         },
         "data": {
           "specifier": "file:///a/file.ts",
@@ -2891,14 +2891,41 @@ fn lsp_code_lens() {
   assert!(maybe_err.is_none());
   assert_eq!(
     maybe_res,
-    Some(load_fixture("code_lens_resolve_response.json"))
+    Some(json!({
+      "range": {
+        "start": { "line": 0, "character": 6 },
+        "end": { "line": 0, "character": 7 }
+      },
+      "command": {
+        "title": "2 references",
+        "command": "deno.showReferences",
+        "arguments": [
+          "file:///a/file.ts",
+          { "line": 0, "character": 6 },
+          [{
+            "uri": "file:///a/file.ts",
+            "range": {
+              "start": { "line": 0, "character": 6 },
+              "end": { "line": 0, "character": 7 }
+            }
+          }, {
+            "uri": "file:///a/file.ts",
+            "range": {
+              "start": { "line": 12, "character": 14 },
+              "end": { "line": 12, "character": 15 }
+            }
+          }]
+        ]
+      }
+    }))
   );
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_code_lens_impl() {
-  let mut client = init("initialize_params.json");
+  let mut client = LspClientBuilder::new().build();
+  client.initialize_default();
   did_open(
     &mut client,
     json!({
@@ -2923,21 +2950,69 @@ fn lsp_code_lens_impl() {
   assert!(maybe_err.is_none());
   assert_eq!(
     maybe_res,
-    Some(load_fixture("code_lens_response_impl.json"))
+    Some(json!([ {
+      "range": {
+        "start": { "line": 0, "character": 10 },
+        "end": { "line": 0, "character": 11 }
+      },
+      "data": {
+        "specifier": "file:///a/file.ts",
+        "source": "implementations"
+      }
+    }, {
+      "range": {
+        "start": { "line": 0, "character": 10 },
+        "end": { "line": 0, "character": 11 }
+      },
+      "data": {
+        "specifier": "file:///a/file.ts",
+        "source": "references"
+      }
+    }, {
+      "range": {
+        "start": { "line": 4, "character": 6 },
+        "end": { "line": 4, "character": 7 }
+      },
+      "data": {
+        "specifier": "file:///a/file.ts",
+        "source": "references"
+      }
+    }, {
+      "range": {
+        "start": { "line": 10, "character": 10 },
+        "end": { "line": 10, "character": 11 }
+      },
+      "data": {
+        "specifier": "file:///a/file.ts",
+        "source": "implementations"
+      }
+    }, {
+      "range": {
+        "start": { "line": 10, "character": 10 },
+        "end": { "line": 10, "character": 11 }
+      },
+      "data": {
+        "specifier": "file:///a/file.ts",
+        "source": "references"
+      }
+    }, {
+      "range": {
+        "start": { "line": 11, "character": 2 },
+        "end": { "line": 11, "character": 3 }
+      },
+      "data": {
+        "specifier": "file:///a/file.ts",
+        "source": "references"
+      }
+    }]))
   );
   let (maybe_res, maybe_err) = client
     .write_request(
       "codeLens/resolve",
       json!({
         "range": {
-          "start": {
-            "line": 0,
-            "character": 10
-          },
-          "end": {
-            "line": 0,
-            "character": 11
-          }
+          "start": { "line": 0, "character": 10 },
+          "end": { "line": 0, "character": 11 }
         },
         "data": {
           "specifier": "file:///a/file.ts",
@@ -2949,21 +3024,35 @@ fn lsp_code_lens_impl() {
   assert!(maybe_err.is_none());
   assert_eq!(
     maybe_res,
-    Some(load_fixture("code_lens_resolve_response_impl.json"))
+    Some(json!({
+      "range": {
+        "start": { "line": 0, "character": 10 },
+        "end": { "line": 0, "character": 11 }
+      },
+      "command": {
+        "title": "1 implementation",
+        "command": "deno.showReferences",
+        "arguments": [
+          "file:///a/file.ts",
+          { "line": 0, "character": 10 },
+          [{
+            "uri": "file:///a/file.ts",
+            "range": {
+              "start": { "line": 4, "character": 6 },
+              "end": { "line": 4, "character": 7 }
+            }
+          }]
+        ]
+      }
+    }))
   );
   let (maybe_res, maybe_err) = client
     .write_request::<_, _, Value>(
       "codeLens/resolve",
       json!({
         "range": {
-          "start": {
-            "line": 10,
-            "character": 10
-          },
-          "end": {
-            "line": 10,
-            "character": 11
-          }
+          "start": { "line": 10, "character": 10 },
+          "end": { "line": 10, "character": 11 }
         },
         "data": {
           "specifier": "file:///a/file.ts",
@@ -2977,14 +3066,8 @@ fn lsp_code_lens_impl() {
     maybe_res,
     Some(json!({
       "range": {
-        "start": {
-          "line": 10,
-          "character": 10
-        },
-        "end": {
-          "line": 10,
-          "character": 11
-        }
+        "start": { "line": 10, "character": 10 },
+        "end": { "line": 10, "character": 11 }
       },
       "command": {
         "title": "0 implementations",
@@ -2992,15 +3075,25 @@ fn lsp_code_lens_impl() {
       }
     }))
   );
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_code_lens_test() {
-  let mut client = init("initialize_params_code_lens_test.json");
+  let mut client = LspClientBuilder::new().build();
+  client.initialize(|builder| {
+    builder.disable_testing_api().set_code_lens(None);
+  });
   did_open(
     &mut client,
-    load_fixture("did_open_params_test_code_lens.json"),
+    json!({
+      "textDocument": {
+        "uri": "file:///a/file.ts",
+        "languageId": "typescript",
+        "version": 1,
+        "text": "const { test } = Deno;\nconst { test: test2 } = Deno;\nconst test3 = Deno.test;\n\nDeno.test(\"test a\", () => {});\nDeno.test({\n  name: \"test b\",\n  fn() {},\n});\ntest({\n  name: \"test c\",\n  fn() {},\n});\ntest(\"test d\", () => {});\ntest2({\n  name: \"test e\",\n  fn() {},\n});\ntest2(\"test f\", () => {});\ntest3({\n  name: \"test g\",\n  fn() {},\n});\ntest3(\"test h\", () => {});\n"
+      }
+    }),
   );
   let (maybe_res, maybe_err) = client
     .write_request(
@@ -3015,18 +3108,256 @@ fn lsp_code_lens_test() {
   assert!(maybe_err.is_none());
   assert_eq!(
     maybe_res,
-    Some(load_fixture("code_lens_response_test.json"))
-  );
-  shutdown(&mut client);
-}
+    Some(json!([{
+      "range": {
+        "start": { "line": 4, "character": 5 },
+        "end": { "line": 4, "character": 9 }
+      },
+      "command": {
+        "title": "▶︎ Run Test",
+        "command": "deno.test",
+        "arguments": [
+          "file:///a/file.ts",
+          "test a",
+          { "inspect": false }
+        ]
+      }
+    }, {
+      "range": {
+        "start": { "line": 4, "character": 5 },
+        "end": { "line": 4, "character": 9 }
+      },
+      "command": {
+        "title": "Debug",
+        "command": "deno.test",
+        "arguments": [
+          "file:///a/file.ts",
+          "test a",
+          { "inspect": true }
+        ]
+      }
+    }, {
+      "range": {
+        "start": { "line": 5, "character": 5 },
+        "end": { "line": 5, "character": 9 }
+      },
+      "command": {
+        "title": "▶︎ Run Test",
+        "command": "deno.test",
+        "arguments": [
+          "file:///a/file.ts",
+          "test b",
+          { "inspect": false }
+        ]
+      }
+    }, {
+      "range": {
+        "start": { "line": 5, "character": 5 },
+        "end": { "line": 5, "character": 9 }
+      },
+      "command": {
+        "title": "Debug",
+        "command": "deno.test",
+        "arguments": [
+          "file:///a/file.ts",
+          "test b",
+          { "inspect": true }
+        ]
+      }
+    }, {
+      "range": {
+        "start": { "line": 9, "character": 0 },
+        "end": { "line": 9, "character": 4 }
+      },
+      "command": {
+        "title": "▶︎ Run Test",
+        "command": "deno.test",
+        "arguments": [
+          "file:///a/file.ts",
+          "test c",
+          { "inspect": false }
+        ]
+      }
+    }, {
+      "range": {
+        "start": { "line": 9, "character": 0 },
+        "end": { "line": 9, "character": 4 }
+      },
+      "command": {
+        "title": "Debug",
+        "command": "deno.test",
+        "arguments": [
+          "file:///a/file.ts",
+          "test c",
+          { "inspect": true }
+        ]
+      }
+    }, {
+      "range": {
+        "start": { "line": 13, "character": 0 },
+        "end": { "line": 13, "character": 4 }
+      },
+      "command": {
+        "title": "▶︎ Run Test",
+        "command": "deno.test",
+        "arguments": [
+          "file:///a/file.ts",
+          "test d",
+          { "inspect": false }
+        ]
+      }
+    }, {
+      "range": {
+        "start": { "line": 13, "character": 0 },
+        "end": { "line": 13, "character": 4 }
+      },
+      "command": {
+        "title": "Debug",
+        "command": "deno.test",
+        "arguments": [
+          "file:///a/file.ts",
+          "test d",
+          { "inspect": true }
+        ]
+      }
+    }, {
+      "range": {
+        "start": { "line": 14, "character": 0 },
+        "end": { "line": 14, "character": 5 }
+      },
+      "command": {
+        "title": "▶︎ Run Test",
+        "command": "deno.test",
+        "arguments": [
+          "file:///a/file.ts",
+          "test e",
+          { "inspect": false }
+        ]
+      }
+    }, {
+      "range": {
+        "start": { "line": 14, "character": 0 },
+        "end": { "line": 14, "character": 5 }
+      },
+      "command": {
+        "title": "Debug",
+        "command": "deno.test",
+        "arguments": [
+          "file:///a/file.ts",
+          "test e",
+          { "inspect": true }
+        ]
+      }
+    }, {
+      "range": {
+        "start": { "line": 18, "character": 0 },
+        "end": { "line": 18, "character": 5 }
+      },
+      "command": {
+        "title": "▶︎ Run Test",
+        "command": "deno.test",
+        "arguments": [
+          "file:///a/file.ts",
+          "test f",
+          { "inspect": false }
+        ]
+      }
+    }, {
+      "range": {
+        "start": { "line": 18, "character": 0 },
+        "end": { "line": 18, "character": 5 }
+      },
+      "command": {
+        "title": "Debug",
+        "command": "deno.test",
+        "arguments": [
+          "file:///a/file.ts",
+          "test f",
+          { "inspect": true }
+        ]
+      }
+    }, {
+      "range": {
+        "start": { "line": 19, "character": 0 },
+        "end": { "line": 19, "character": 5 }
+      },
+      "command": {
+        "title": "▶︎ Run Test",
+        "command": "deno.test",
+        "arguments": [
+          "file:///a/file.ts",
+          "test g",
+          { "inspect": false }
+        ]
+      }
+    }, {
+      "range": {
+        "start": { "line": 19, "character": 0 },
+        "end": { "line": 19, "character": 5 }
+      },
+      "command": {
+        "title": "Debug",
+        "command": "deno.test",
+        "arguments": [
+          "file:///a/file.ts",
+          "test g",
+          { "inspect": true }
+        ]
+      }
+    }, {
+      "range": {
+        "start": { "line": 23, "character": 0 },
+        "end": { "line": 23, "character": 5 }
+      },
+      "command": {
+        "title": "▶︎ Run Test",
+        "command": "deno.test",
+        "arguments": [
+          "file:///a/file.ts",
+          "test h",
+          { "inspect": false }
+        ]
+      }
+    }, {
+      "range": {
+        "start": { "line": 23, "character": 0 },
+        "end": { "line": 23, "character": 5 }
+      },
+      "command": {
+        "title": "Debug",
+        "command": "deno.test",
+        "arguments": [
+          "file:///a/file.ts",
+          "test h",
+          { "inspect": true }
+        ]
+      }
+    }]))
+  );
+  client.shutdown();
+}
 
 #[test]
 fn lsp_code_lens_test_disabled() {
-  let mut client = init("initialize_params_code_lens_test_disabled.json");
+  let mut client = LspClientBuilder::new().build();
+  client.initialize(|builder| {
+    builder.disable_testing_api().set_code_lens(Some(json!({
+      "implementations": true,
+      "references": true,
+      "test": false
+    })));
+  });
   client
     .write_notification(
       "textDocument/didOpen",
-      load_fixture("did_open_params_test_code_lens.json"),
+      json!({
+        "textDocument": {
+          "uri": "file:///a/file.ts",
+          "languageId": "typescript",
+          "version": 1,
+          "text": "const { test } = Deno;\nconst { test: test2 } = Deno;\nconst test3 = Deno.test;\n\nDeno.test(\"test a\", () => {});\nDeno.test({\n  name: \"test b\",\n  fn() {},\n});\ntest({\n  name: \"test c\",\n  fn() {},\n});\ntest(\"test d\", () => {});\ntest2({\n  name: \"test e\",\n  fn() {},\n});\ntest2(\"test f\", () => {});\ntest3({\n  name: \"test g\",\n  fn() {},\n});\ntest3(\"test h\", () => {});\n"
+        }
+      }),
     )
     .unwrap();
 
@@ -3062,12 +3393,13 @@ fn lsp_code_lens_test_disabled() {
     .unwrap();
   assert!(maybe_err.is_none());
   assert_eq!(maybe_res, Some(json!([])));
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_code_lens_non_doc_nav_tree() {
-  let mut client = init("initialize_params.json");
+  let mut client = LspClientBuilder::new().build();
+  client.initialize_default();
   did_open(
     &mut client,
     json!({
@@ -3086,10 +3418,7 @@ fn lsp_code_lens_non_doc_nav_tree() {
         "textDocument": {
           "uri": "file:///a/file.ts"
         },
-        "position": {
-          "line": 0,
-          "character": 3
-        },
+        "position": { "line": 0, "character": 3 },
         "context": {
           "includeDeclaration": true
         }
@@ -3129,14 +3458,8 @@ fn lsp_code_lens_non_doc_nav_tree() {
       "codeLens/resolve",
       json!({
         "range": {
-          "start": {
-            "line": 416,
-            "character": 12
-          },
-          "end": {
-            "line": 416,
-            "character": 19
-          }
+          "start": { "line": 416, "character": 12 },
+          "end": { "line": 416, "character": 19 }
         },
         "data": {
           "specifier": "asset:///lib.deno.shared_globals.d.ts",
@@ -3147,12 +3470,13 @@ fn lsp_code_lens_non_doc_nav_tree() {
     .unwrap();
   assert!(maybe_err.is_none());
   assert!(maybe_res.is_some());
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_nav_tree_updates() {
-  let mut client = init("initialize_params.json");
+  let mut client = LspClientBuilder::new().build();
+  client.initialize_default();
   did_open(
     &mut client,
     json!({
@@ -3177,7 +3501,61 @@ fn lsp_nav_tree_updates() {
   assert!(maybe_err.is_none());
   assert_eq!(
     maybe_res,
-    Some(load_fixture("code_lens_response_impl.json"))
+    Some(Some(json!([ {
+      "range": {
+        "start": { "line": 0, "character": 10 },
+        "end": { "line": 0, "character": 11 }
+      },
+      "data": {
+        "specifier": "file:///a/file.ts",
+        "source": "implementations"
+      }
+    }, {
+      "range": {
+        "start": { "line": 0, "character": 10 },
+        "end": { "line": 0, "character": 11 }
+      },
+      "data": {
+        "specifier": "file:///a/file.ts",
+        "source": "references"
+      }
+    }, {
+      "range": {
+        "start": { "line": 4, "character": 6 },
+        "end": { "line": 4, "character": 7 }
+      },
+      "data": {
+        "specifier": "file:///a/file.ts",
+        "source": "references"
+      }
+    }, {
+      "range": {
+        "start": { "line": 10, "character": 10 },
+        "end": { "line": 10, "character": 11 }
+      },
+      "data": {
+        "specifier": "file:///a/file.ts",
+        "source": "implementations"
+      }
+    }, {
+      "range": {
+        "start": { "line": 10, "character": 10 },
+        "end": { "line": 10, "character": 11 }
+      },
+      "data": {
+        "specifier": "file:///a/file.ts",
+        "source": "references"
+      }
+    }, {
+      "range": {
+        "start": { "line": 11, "character": 2 },
+        "end": { "line": 11, "character": 3 }
+      },
+      "data": {
+        "specifier": "file:///a/file.ts",
+        "source": "references"
+      }
+    }])))
   );
   client
     .write_notification(
@@ -3190,14 +3568,8 @@ fn lsp_nav_tree_updates() {
         "contentChanges": [
           {
             "range": {
-              "start": {
-                "line": 10,
-                "character": 0
-              },
-              "end": {
-                "line": 13,
-                "character": 0
-              }
+              "start": { "line": 10, "character": 0 },
+              "end": { "line": 13, "character": 0 }
             },
             "text": ""
           }
@@ -3218,14 +3590,42 @@ fn lsp_nav_tree_updates() {
   assert!(maybe_err.is_none());
   assert_eq!(
     maybe_res,
-    Some(load_fixture("code_lens_response_changed.json"))
+    Some(json!([{
+      "range": {
+        "start": { "line": 0, "character": 10 },
+        "end": { "line": 0, "character": 11 }
+      },
+      "data": {
+        "specifier": "file:///a/file.ts",
+        "source": "implementations"
+      }
+    }, {
+      "range": {
+        "start": { "line": 0, "character": 10 },
+        "end": { "line": 0, "character": 11 }
+      },
+      "data": {
+        "specifier": "file:///a/file.ts",
+        "source": "references"
+      }
+    }, {
+      "range": {
+        "start": { "line": 4, "character": 6 },
+        "end": { "line": 4, "character": 7 }
+      },
+      "data": {
+        "specifier": "file:///a/file.ts",
+        "source": "references"
+      }
+    }]))
   );
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_signature_help() {
-  let mut client = init("initialize_params.json");
+  let mut client = LspClientBuilder::new().build();
+  client.initialize_default();
   did_open(
     &mut client,
     json!({
@@ -3244,10 +3644,7 @@ fn lsp_signature_help() {
         "textDocument": {
           "uri": "file:///a/file.ts"
         },
-        "position": {
-          "character": 4,
-          "line": 9
-        },
+        "position": { "character": 4, "line": 9 },
         "context": {
           "triggerKind": 2,
           "triggerCharacter": "(",
@@ -3274,8 +3671,7 @@ fn lsp_signature_help() {
                 "kind": "markdown",
                 "value": "This is a first number."
               }
-            },
-            {
+            }, {
               "label": "b: number",
               "documentation": {
                 "kind": "markdown",
@@ -3300,14 +3696,8 @@ fn lsp_signature_help() {
         "contentChanges": [
           {
             "range": {
-              "start": {
-                "line": 9,
-                "character": 4
-              },
-              "end": {
-                "line": 9,
-                "character": 4
-              }
+              "start": { "line": 9, "character": 4 },
+              "end": { "line": 9, "character": 4 }
             },
             "text": "123, "
           }
@@ -3322,10 +3712,7 @@ fn lsp_signature_help() {
         "textDocument": {
           "uri": "file:///a/file.ts"
         },
-        "position": {
-          "character": 8,
-          "line": 9
-        }
+        "position": { "character": 8, "line": 9 }
       }),
     )
     .unwrap();
@@ -3347,8 +3734,7 @@ fn lsp_signature_help() {
                 "kind": "markdown",
                 "value": "This is a first number."
               }
-            },
-            {
+            }, {
               "label": "b: number",
               "documentation": {
                 "kind": "markdown",
@@ -3362,12 +3748,13 @@ fn lsp_signature_help() {
       "activeParameter": 1
     }))
   );
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_code_actions() {
-  let mut client = init("initialize_params.json");
+  let mut client = LspClientBuilder::new().build();
+  client.initialize_default();
   did_open(
     &mut client,
     json!({
@@ -3382,28 +3769,185 @@ fn lsp_code_actions() {
   let (maybe_res, maybe_err) = client
     .write_request(
       "textDocument/codeAction",
-      load_fixture("code_action_params.json"),
+      json!({
+        "textDocument": {
+          "uri": "file:///a/file.ts"
+        },
+        "range": {
+          "start": { "line": 1, "character": 2 },
+          "end": { "line": 1, "character": 7 }
+        },
+        "context": {
+          "diagnostics": [{
+            "range": {
+              "start": { "line": 1, "character": 2 },
+              "end": { "line": 1, "character": 7 }
+            },
+            "severity": 1,
+            "code": 1308,
+            "source": "deno-ts",
+            "message": "'await' expressions are only allowed within async functions and at the top levels of modules.",
+            "relatedInformation": []
+          }],
+          "only": ["quickfix"]
+        }
+      }),
     )
     .unwrap();
   assert!(maybe_err.is_none());
-  assert_eq!(maybe_res, Some(load_fixture("code_action_response.json")));
+  assert_eq!(
+    maybe_res,
+    Some(json!([{
+      "title": "Add async modifier to containing function",
+      "kind": "quickfix",
+      "diagnostics": [{
+        "range": {
+          "start": { "line": 1, "character": 2 },
+          "end": { "line": 1, "character": 7 }
+        },
+        "severity": 1,
+        "code": 1308,
+        "source": "deno-ts",
+        "message": "'await' expressions are only allowed within async functions and at the top levels of modules.",
+        "relatedInformation": []
+      }],
+      "edit": {
+        "documentChanges": [{
+          "textDocument": {
+            "uri": "file:///a/file.ts",
+            "version": 1
+          },
+          "edits": [{
+            "range": {
+              "start": { "line": 0, "character": 7 },
+              "end": { "line": 0, "character": 7 }
+            },
+            "newText": "async "
+          }, {
+            "range": {
+              "start": { "line": 0, "character": 21 },
+              "end": { "line": 0, "character": 25 }
+            },
+            "newText": "Promise<void>"
+          }]
+        }]
+      }
+    }, {
+      "title": "Add all missing 'async' modifiers",
+      "kind": "quickfix",
+      "diagnostics": [{
+        "range": {
+          "start": { "line": 1, "character": 2 },
+          "end": { "line": 1, "character": 7 }
+        },
+        "severity": 1,
+        "code": 1308,
+        "source": "deno-ts",
+        "message": "'await' expressions are only allowed within async functions and at the top levels of modules.",
+        "relatedInformation": []
+      }],
+      "data": {
+        "specifier": "file:///a/file.ts",
+        "fixId": "fixAwaitInSyncFunction"
+      }
+    }]))
+  );
   let (maybe_res, maybe_err) = client
     .write_request(
       "codeAction/resolve",
-      load_fixture("code_action_resolve_params.json"),
+      json!({
+        "title": "Add all missing 'async' modifiers",
+        "kind": "quickfix",
+        "diagnostics": [{
+          "range": {
+            "start": { "line": 1, "character": 2 },
+            "end": { "line": 1, "character": 7 }
+          },
+          "severity": 1,
+          "code": 1308,
+          "source": "deno-ts",
+          "message": "'await' expressions are only allowed within async functions and at the top levels of modules.",
+          "relatedInformation": []
+        }],
+        "data": {
+          "specifier": "file:///a/file.ts",
+          "fixId": "fixAwaitInSyncFunction"
+        }
+      }),
     )
     .unwrap();
   assert!(maybe_err.is_none());
   assert_eq!(
     maybe_res,
-    Some(load_fixture("code_action_resolve_response.json"))
+    Some(json!({
+      "title": "Add all missing 'async' modifiers",
+      "kind": "quickfix",
+      "diagnostics": [
+        {
+          "range": {
+            "start": {
+              "line": 1,
+              "character": 2
+            },
+            "end": {
+              "line": 1,
+              "character": 7
+            }
+          },
+          "severity": 1,
+          "code": 1308,
+          "source": "deno-ts",
+          "message": "'await' expressions are only allowed within async functions and at the top levels of modules.",
+          "relatedInformation": []
+        }
+      ],
+      "edit": {
+        "documentChanges": [{
+          "textDocument": {
+            "uri": "file:///a/file.ts",
+            "version": 1
+          },
+          "edits": [{
+            "range": {
+              "start": { "line": 0, "character": 7 },
+              "end": { "line": 0, "character": 7 }
+            },
+            "newText": "async "
+          }, {
+            "range": {
+              "start": { "line": 0, "character": 21 },
+              "end": { "line": 0, "character": 25 }
+            },
+            "newText": "Promise<void>"
+          }, {
+            "range": {
+              "start": { "line": 4, "character": 7 },
+              "end": { "line": 4, "character": 7 }
+            },
+            "newText": "async "
+          }, {
+            "range": {
+              "start": { "line": 4, "character": 21 },
+              "end": { "line": 4, "character": 25 }
+            },
+            "newText": "Promise<void>"
+          }]
+        }]
+      },
+      "data": {
+        "specifier": "file:///a/file.ts",
+        "fixId": "fixAwaitInSyncFunction"
+      }
+    }))
   );
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_code_actions_deno_cache() {
-  let mut session = TestSession::from_file("initialize_params.json");
+  let mut client = LspClientBuilder::new().build();
+  client.initialize_default();
+  let mut session = TestSession::from_client(client);
   let diagnostics = session.did_open(json!({
       "textDocument": {
         "uri": "file:///a/file.ts",
@@ -3414,27 +3958,88 @@ fn lsp_code_actions_deno_cache() {
     }));
   assert_eq!(
     diagnostics.with_source("deno"),
-    load_fixture_as("diagnostics_deno_deps.json")
+    serde_json::from_value(json!({
+      "uri": "file:///a/file.ts",
+      "diagnostics": [{
+        "range": {
+          "start": { "line": 0, "character": 19 },
+          "end": { "line": 0, "character": 49 }
+        },
+        "severity": 1,
+        "code": "no-cache",
+        "source": "deno",
+        "message": "Uncached or missing remote URL: \"https://deno.land/x/a/mod.ts\".",
+        "data": { "specifier": "https://deno.land/x/a/mod.ts" }
+      }],
+      "version": 1
+    })).unwrap()
   );
 
   let (maybe_res, maybe_err) = session
     .client
     .write_request(
       "textDocument/codeAction",
-      load_fixture("code_action_params_cache.json"),
+      json!({
+        "textDocument": {
+          "uri": "file:///a/file.ts"
+        },
+        "range": {
+          "start": { "line": 0, "character": 19 },
+          "end": { "line": 0, "character": 49 }
+        },
+        "context": {
+          "diagnostics": [{
+            "range": {
+              "start": { "line": 0, "character": 19 },
+              "end": { "line": 0, "character": 49 }
+            },
+            "severity": 1,
+            "code": "no-cache",
+            "source": "deno",
+            "message": "Unable to load the remote module: \"https://deno.land/x/a/mod.ts\".",
+            "data": {
+              "specifier": "https://deno.land/x/a/mod.ts"
+            }
+          }],
+          "only": ["quickfix"]
+        }
+      }),
     )
     .unwrap();
   assert!(maybe_err.is_none());
   assert_eq!(
     maybe_res,
-    Some(load_fixture("code_action_response_cache.json"))
+    Some(json!([{
+      "title": "Cache \"https://deno.land/x/a/mod.ts\" and its dependencies.",
+      "kind": "quickfix",
+      "diagnostics": [{
+        "range": {
+          "start": { "line": 0, "character": 19 },
+          "end": { "line": 0, "character": 49 }
+        },
+        "severity": 1,
+        "code": "no-cache",
+        "source": "deno",
+        "message": "Unable to load the remote module: \"https://deno.land/x/a/mod.ts\".",
+        "data": {
+          "specifier": "https://deno.land/x/a/mod.ts"
+        }
+      }],
+      "command": {
+        "title": "",
+        "command": "deno.cache",
+        "arguments": [["https://deno.land/x/a/mod.ts"]]
+      }
+    }]))
   );
   session.shutdown_and_exit();
 }
 
 #[test]
 fn lsp_code_actions_deno_cache_npm() {
-  let mut session = TestSession::from_file("initialize_params.json");
+  let mut client = LspClientBuilder::new().build();
+  client.initialize_default();
+  let mut session = TestSession::from_client(client);
   let diagnostics = session.did_open(json!({
     "textDocument": {
       "uri": "file:///a/file.ts",
@@ -3445,27 +4050,85 @@ fn lsp_code_actions_deno_cache_npm() {
   }));
   assert_eq!(
     diagnostics.with_source("deno"),
-    load_fixture_as("code_actions/cache_npm/diagnostics.json")
+    serde_json::from_value(json!({
+      "uri": "file:///a/file.ts",
+      "diagnostics": [{
+        "range": {
+          "start": { "line": 0, "character": 18 },
+          "end": { "line": 0, "character": 29 }
+        },
+        "severity": 1,
+        "code": "no-cache-npm",
+        "source": "deno",
+        "message": "Uncached or missing npm package: \"chalk\".",
+        "data": { "specifier": "npm:chalk" }
+      }],
+      "version": 1
+    }))
+    .unwrap()
   );
 
   let (maybe_res, maybe_err) = session
     .client
     .write_request(
       "textDocument/codeAction",
-      load_fixture("code_actions/cache_npm/cache_action.json"),
+      json!({
+        "textDocument": {
+          "uri": "file:///a/file.ts"
+        },
+        "range": {
+          "start": { "line": 0, "character": 18 },
+          "end": { "line": 0, "character": 29 }
+        },
+        "context": {
+          "diagnostics": [{
+            "range": {
+              "start": { "line": 0, "character": 18 },
+              "end": { "line": 0, "character": 29 }
+            },
+            "severity": 1,
+            "code": "no-cache-npm",
+            "source": "deno",
+            "message": "Uncached or missing npm package: \"chalk\".",
+            "data": { "specifier": "npm:chalk" }
+          }],
+          "only": ["quickfix"]
+        }
+      }),
     )
     .unwrap();
   assert!(maybe_err.is_none());
   assert_eq!(
     maybe_res,
-    Some(load_fixture("code_actions/cache_npm/cache_response.json"))
+    Some(json!([{
+      "title": "Cache \"npm:chalk\" and its dependencies.",
+      "kind": "quickfix",
+      "diagnostics": [{
+        "range": {
+          "start": { "line": 0, "character": 18 },
+          "end": { "line": 0, "character": 29 }
+        },
+        "severity": 1,
+        "code": "no-cache-npm",
+        "source": "deno",
+        "message": "Uncached or missing npm package: \"chalk\".",
+        "data": { "specifier": "npm:chalk" }
+      }],
+      "command": {
+        "title": "",
+        "command": "deno.cache",
+        "arguments": [["npm:chalk"]]
+      }
+    }]))
   );
   session.shutdown_and_exit();
 }
 
 #[test]
 fn lsp_code_actions_imports() {
-  let mut session = TestSession::from_file("initialize_params.json");
+  let mut client = LspClientBuilder::new().build();
+  client.initialize_default();
+  let mut session = TestSession::from_client(client);
   session.did_open(json!({
       "textDocument": {
         "uri": "file:///a/file00.ts",
@@ -3516,25 +4179,195 @@ export class DuckConfig {
     .client
     .write_request(
       "textDocument/codeAction",
-      load_fixture("code_action_params_imports.json"),
+      json!({
+        "textDocument": {
+          "uri": "file:///a/file00.ts"
+        },
+        "range": {
+          "start": { "line": 0, "character": 0 },
+          "end": { "line": 6, "character": 0 }
+        },
+        "context": {
+          "diagnostics": [{
+            "range": {
+              "start": { "line": 0, "character": 50 },
+              "end": { "line": 0, "character": 67 }
+            },
+            "severity": 1,
+            "code": 2304,
+            "source": "deno-ts",
+            "message": "Cannot find name 'DuckConfigOptions'."
+          }, {
+            "range": {
+              "start": { "line": 4, "character": 39 },
+              "end": { "line": 4, "character": 49 }
+            },
+            "severity": 1,
+            "code": 2304,
+            "source": "deno-ts",
+            "message": "Cannot find name 'DuckConfig'."
+          }],
+          "only": ["quickfix"]
+        }
+      }),
     )
     .unwrap();
   assert!(maybe_err.is_none());
   assert_eq!(
     maybe_res,
-    Some(load_fixture("code_action_response_imports.json"))
+    Some(json!([{
+      "title": "Add import from \"./file02.ts\"",
+      "kind": "quickfix",
+      "diagnostics": [{
+        "range": {
+          "start": { "line": 0, "character": 50 },
+          "end": { "line": 0, "character": 67 }
+        },
+        "severity": 1,
+        "code": 2304,
+        "source": "deno-ts",
+        "message": "Cannot find name 'DuckConfigOptions'."
+      }],
+      "edit": {
+        "documentChanges": [{
+          "textDocument": {
+            "uri": "file:///a/file00.ts",
+            "version": 1
+          },
+          "edits": [{
+            "range": {
+              "start": { "line": 0, "character": 0 },
+              "end": { "line": 0, "character": 0 }
+            },
+            "newText": "import { DuckConfigOptions } from \"./file02.ts\";\n\n"
+          }]
+        }]
+      }
+    }, {
+      "title": "Add all missing imports",
+      "kind": "quickfix",
+      "diagnostics": [{
+        "range": {
+          "start": { "line": 0, "character": 50 },
+          "end": { "line": 0, "character": 67 }
+        },
+        "severity": 1,
+        "code": 2304,
+        "source": "deno-ts",
+        "message": "Cannot find name 'DuckConfigOptions'."
+      }],
+      "data": {
+        "specifier": "file:///a/file00.ts",
+        "fixId": "fixMissingImport"
+      }
+    }, {
+      "title": "Add import from \"./file01.ts\"",
+      "kind": "quickfix",
+      "diagnostics": [{
+        "range": {
+          "start": { "line": 4, "character": 39 },
+          "end": { "line": 4, "character": 49 }
+        },
+        "severity": 1,
+        "code": 2304,
+        "source": "deno-ts",
+        "message": "Cannot find name 'DuckConfig'."
+      }],
+      "edit": {
+        "documentChanges": [{
+          "textDocument": {
+            "uri": "file:///a/file00.ts",
+            "version": 1
+          },
+          "edits": [{
+            "range": {
+              "start": { "line": 0, "character": 0 },
+              "end": { "line": 0, "character": 0 }
+            },
+            "newText": "import { DuckConfig } from \"./file01.ts\";\n\n"
+          }]
+        }]
+      }
+    }]))
   );
   let (maybe_res, maybe_err) = session
     .client
     .write_request(
       "codeAction/resolve",
-      load_fixture("code_action_resolve_params_imports.json"),
+      json!({
+        "title": "Add all missing imports",
+        "kind": "quickfix",
+        "diagnostics": [{
+          "range": {
+            "start": { "line": 0, "character": 50 },
+            "end": { "line": 0, "character": 67 }
+          },
+          "severity": 1,
+          "code": 2304,
+          "source": "deno-ts",
+          "message": "Cannot find name 'DuckConfigOptions'."
+        }, {
+          "range": {
+            "start": { "line": 4, "character": 39 },
+            "end": { "line": 4, "character": 49 }
+          },
+          "severity": 1,
+          "code": 2304,
+          "source": "deno-ts",
+          "message": "Cannot find name 'DuckConfig'."
+        }],
+        "data": {
+          "specifier": "file:///a/file00.ts",
+          "fixId": "fixMissingImport"
+        }
+      }),
     )
     .unwrap();
   assert!(maybe_err.is_none());
   assert_eq!(
     maybe_res,
-    Some(load_fixture("code_action_resolve_response_imports.json"))
+    Some(json!({
+      "title": "Add all missing imports",
+      "kind": "quickfix",
+      "diagnostics": [{
+        "range": {
+          "start": { "line": 0, "character": 50 },
+          "end": { "line": 0, "character": 67 }
+        },
+        "severity": 1,
+        "code": 2304,
+        "source": "deno-ts",
+        "message": "Cannot find name 'DuckConfigOptions'."
+      }, {
+        "range": {
+          "start": { "line": 4, "character": 39 },
+          "end": { "line": 4, "character": 49 }
+        },
+        "severity": 1,
+        "code": 2304,
+        "source": "deno-ts",
+        "message": "Cannot find name 'DuckConfig'."
+      }],
+      "edit": {
+        "documentChanges": [{
+          "textDocument": {
+            "uri": "file:///a/file00.ts",
+            "version": 1
+          },
+          "edits": [{
+            "range": {
+              "start": { "line": 0, "character": 0 },
+              "end": { "line": 0, "character": 0 }
+            },
+            "newText": "import { DuckConfig } from \"./file01.ts\";\nimport { DuckConfigOptions } from \"./file02.ts\";\n\n"
+          }]
+        }]
+      },
+      "data": {
+        "specifier": "file:///a/file00.ts",
+        "fixId": "fixMissingImport"
+      }
+    }))
   );
 
   session.shutdown_and_exit();
@@ -3542,7 +4375,8 @@ export class DuckConfig {
 
 #[test]
 fn lsp_code_actions_refactor() {
-  let mut client = init("initialize_params.json");
+  let mut client = LspClientBuilder::new().build();
+  client.initialize_default();
   did_open(
     &mut client,
     json!({
@@ -3552,36 +4386,221 @@ fn lsp_code_actions_refactor() {
         "version": 1,
         "text": "var x: { a?: number; b?: string } = {};\n"
       }
-    }),
-  );
-  let (maybe_res, maybe_err) = client
-    .write_request(
-      "textDocument/codeAction",
-      load_fixture("code_action_params_refactor.json"),
-    )
-    .unwrap();
-  assert!(maybe_err.is_none());
-  assert_eq!(
-    maybe_res,
-    Some(load_fixture("code_action_response_refactor.json"))
+    }),
+  );
+  let (maybe_res, maybe_err) = client
+    .write_request(
+      "textDocument/codeAction",
+      json!({
+        "textDocument": {
+          "uri": "file:///a/file.ts"
+        },
+        "range": {
+          "start": { "line": 0, "character": 0 },
+          "end": { "line": 1, "character": 0 }
+        },
+        "context": {
+          "diagnostics": [],
+          "only": ["refactor"]
+        }
+      }),
+    )
+    .unwrap();
+  assert!(maybe_err.is_none());
+  assert_eq!(
+    maybe_res,
+    Some(json!([{
+      "title": "Extract to function in module scope",
+      "kind": "refactor.extract.function",
+      "isPreferred": false,
+      "data": {
+        "specifier": "file:///a/file.ts",
+        "range": {
+          "start": { "line": 0, "character": 0 },
+          "end": { "line": 1, "character": 0 }
+        },
+        "refactorName": "Extract Symbol",
+        "actionName": "function_scope_0"
+      }
+    }, {
+      "title": "Extract to constant in enclosing scope",
+      "kind": "refactor.extract.constant",
+      "isPreferred": false,
+      "data": {
+        "specifier": "file:///a/file.ts",
+        "range": {
+          "start": { "line": 0, "character": 0 },
+          "end": { "line": 1, "character": 0 }
+        },
+        "refactorName": "Extract Symbol",
+        "actionName": "constant_scope_0"
+      }
+    }, {
+      "title": "Move to a new file",
+      "kind": "refactor.move.newFile",
+      "isPreferred": false,
+      "data": {
+        "specifier": "file:///a/file.ts",
+        "range": {
+          "start": { "line": 0, "character": 0 },
+          "end": { "line": 1, "character": 0 }
+        },
+        "refactorName": "Move to a new file",
+        "actionName": "Move to a new file"
+      }
+    }, {
+      "title": "Convert default export to named export",
+      "kind": "refactor.rewrite.export.named",
+      "isPreferred": false,
+      "disabled": {
+        "reason": "This file already has a default export"
+      },
+      "data": {
+        "specifier": "file:///a/file.ts",
+        "range": {
+          "start": { "line": 0, "character": 0 },
+          "end": { "line": 1, "character": 0 }
+        },
+        "refactorName": "Convert export",
+        "actionName": "Convert default export to named export"
+      }
+    }, {
+      "title": "Convert named export to default export",
+      "kind": "refactor.rewrite.export.default",
+      "isPreferred": false,
+      "disabled": {
+        "reason": "This file already has a default export"
+      },
+      "data": {
+        "specifier": "file:///a/file.ts",
+        "range": {
+          "start": { "line": 0, "character": 0 },
+          "end": { "line": 1, "character": 0 }
+        },
+        "refactorName": "Convert export",
+        "actionName": "Convert named export to default export"
+      }
+    }, {
+      "title": "Convert namespace import to named imports",
+      "kind": "refactor.rewrite.import.named",
+      "isPreferred": false,
+      "disabled": {
+        "reason": "Selection is not an import declaration."
+      },
+      "data": {
+        "specifier": "file:///a/file.ts",
+        "range": {
+          "start": { "line": 0, "character": 0 },
+          "end": { "line": 1, "character": 0 }
+        },
+        "refactorName": "Convert import",
+        "actionName": "Convert namespace import to named imports"
+      }
+    }, {
+      "title": "Convert named imports to default import",
+      "kind": "refactor.rewrite.import.default",
+      "isPreferred": false,
+      "disabled": {
+        "reason": "Selection is not an import declaration."
+      },
+      "data": {
+        "specifier": "file:///a/file.ts",
+        "range": {
+          "start": { "line": 0, "character": 0 },
+          "end": { "line": 1, "character": 0 }
+        },
+        "refactorName": "Convert import",
+        "actionName": "Convert named imports to default import"
+      }
+    }, {
+      "title": "Convert named imports to namespace import",
+      "kind": "refactor.rewrite.import.namespace",
+      "isPreferred": false,
+      "disabled": {
+        "reason": "Selection is not an import declaration."
+      },
+      "data": {
+        "specifier": "file:///a/file.ts",
+        "range": {
+          "start": { "line": 0, "character": 0 },
+          "end": { "line": 1, "character": 0 }
+        },
+        "refactorName": "Convert import",
+        "actionName": "Convert named imports to namespace import"
+      }
+    }]))
   );
   let (maybe_res, maybe_err) = client
     .write_request(
       "codeAction/resolve",
-      load_fixture("code_action_resolve_params_refactor.json"),
+      json!({
+        "title": "Extract to interface",
+        "kind": "refactor.extract.interface",
+        "isPreferred": true,
+        "data": {
+          "specifier": "file:///a/file.ts",
+          "range": {
+            "start": { "line": 0, "character": 7 },
+            "end": { "line": 0, "character": 33 }
+          },
+          "refactorName": "Extract type",
+          "actionName": "Extract to interface"
+        }
+      }),
     )
     .unwrap();
   assert!(maybe_err.is_none());
   assert_eq!(
     maybe_res,
-    Some(load_fixture("code_action_resolve_response_refactor.json"))
+    Some(json!({
+      "title": "Extract to interface",
+      "kind": "refactor.extract.interface",
+      "edit": {
+        "documentChanges": [{
+          "textDocument": {
+            "uri": "file:///a/file.ts",
+            "version": 1
+          },
+          "edits": [{
+            "range": {
+              "start": { "line": 0, "character": 0 },
+              "end": { "line": 0, "character": 0 }
+            },
+            "newText": "interface NewType {\n  a?: number;\n  b?: string;\n}\n\n"
+          }, {
+            "range": {
+              "start": { "line": 0, "character": 7 },
+              "end": { "line": 0, "character": 33 }
+            },
+            "newText": "NewType"
+          }]
+        }]
+      },
+      "isPreferred": true,
+      "data": {
+        "specifier": "file:///a/file.ts",
+        "range": {
+          "start": { "line": 0, "character": 7 },
+          "end": { "line": 0, "character": 33 }
+        },
+        "refactorName": "Extract type",
+        "actionName": "Extract to interface"
+      }
+    }))
   );
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_code_actions_refactor_no_disabled_support() {
-  let mut client = init("initialize_params_ca_no_disabled.json");
+  let mut client = LspClientBuilder::new().build();
+  client.initialize(|builder| {
+    builder.with_capabilities(|c| {
+      let doc = c.text_document.as_mut().unwrap();
+      let code_action = doc.code_action.as_mut().unwrap();
+      code_action.disabled_support = Some(false);
+    });
+  });
   did_open(
     &mut client,
     json!({
@@ -3601,20 +4620,12 @@ fn lsp_code_actions_refactor_no_disabled_support() {
           "uri": "file:///a/file.ts"
         },
         "range": {
-          "start": {
-            "line": 0,
-            "character": 0
-          },
-          "end": {
-            "line": 14,
-            "character": 0
-          }
+          "start": { "line": 0, "character": 0 },
+          "end": { "line": 14, "character": 0 }
         },
         "context": {
           "diagnostics": [],
-          "only": [
-            "refactor"
-          ]
+          "only": ["refactor"]
         }
       }),
     )
@@ -3622,18 +4633,55 @@ fn lsp_code_actions_refactor_no_disabled_support() {
   assert!(maybe_err.is_none());
   assert_eq!(
     maybe_res,
-    Some(load_fixture("code_action_response_no_disabled.json"))
+    Some(json!([{
+      "title": "Extract to function in module scope",
+      "kind": "refactor.extract.function",
+      "isPreferred": false,
+      "data": {
+        "specifier": "file:///a/file.ts",
+        "range": {
+          "start": { "line": 0, "character": 0 },
+          "end": { "line": 14, "character": 0 }
+        },
+        "refactorName": "Extract Symbol",
+        "actionName": "function_scope_0"
+      }
+    }, {
+      "title": "Move to a new file",
+      "kind": "refactor.move.newFile",
+      "isPreferred": false,
+      "data": {
+        "specifier": "file:///a/file.ts",
+        "range": {
+          "start": { "line": 0, "character": 0 },
+          "end": { "line": 14, "character": 0 }
+        },
+        "refactorName": "Move to a new file",
+        "actionName": "Move to a new file"
+      }
+    }]))
   );
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_code_actions_deadlock() {
-  let mut client = init("initialize_params.json");
+  let mut client = LspClientBuilder::new().build();
+  client.initialize_default();
+  let large_file_text =
+    fs::read_to_string(testdata_path().join("lsp").join("large_file.txt"))
+      .unwrap();
   client
     .write_notification(
       "textDocument/didOpen",
-      load_fixture("did_open_params_large.json"),
+      json!({
+        "textDocument": {
+          "uri": "file:///a/file.ts",
+          "languageId": "javascript",
+          "version": 1,
+          "text": large_file_text,
+        }
+      }),
     )
     .unwrap();
   let (id, method, _) = client.read_request::<Value>().unwrap();
@@ -3665,14 +4713,8 @@ fn lsp_code_actions_deadlock() {
         "contentChanges": [
           {
             "range": {
-              "start": {
-                "line": 444,
-                "character": 11
-              },
-              "end": {
-                "line": 444,
-                "character": 14
-              }
+              "start": { "line": 444, "character": 11 },
+              "end": { "line": 444, "character": 14 }
             },
             "text": "+++"
           }
@@ -3691,14 +4733,8 @@ fn lsp_code_actions_deadlock() {
         "contentChanges": [
           {
             "range": {
-              "start": {
-                "line": 445,
-                "character": 4
-              },
-              "end": {
-                "line": 445,
-                "character": 4
-              }
+              "start": { "line": 445, "character": 4 },
+              "end": { "line": 445, "character": 4 }
             },
             "text": "// "
           }
@@ -3717,14 +4753,8 @@ fn lsp_code_actions_deadlock() {
         "contentChanges": [
           {
             "range": {
-              "start": {
-                "line": 477,
-                "character": 4
-              },
-              "end": {
-                "line": 477,
-                "character": 9
-              }
+              "start": { "line": 477, "character": 4 },
+              "end": { "line": 477, "character": 9 }
             },
             "text": "error"
           }
@@ -3743,10 +4773,7 @@ fn lsp_code_actions_deadlock() {
         "textDocument": {
           "uri": "file:///a/file.ts",
         },
-        "position": {
-          "line": 609,
-          "character": 33,
-        }
+        "position": { "line": 609, "character": 33, }
       }),
     )
     .unwrap();
@@ -3755,7 +4782,28 @@ fn lsp_code_actions_deadlock() {
   let (maybe_res, maybe_err) = client
     .write_request::<_, _, Value>(
       "textDocument/codeAction",
-      load_fixture("code_action_params_deadlock.json"),
+      json!({
+        "textDocument": {
+          "uri": "file:///a/file.ts"
+        },
+        "range": {
+          "start": { "line": 441, "character": 33 },
+          "end": { "line": 441, "character": 42 }
+        },
+        "context": {
+          "diagnostics": [{
+            "range": {
+              "start": { "line": 441, "character": 33 },
+              "end": { "line": 441, "character": 42 }
+            },
+            "severity": 1,
+            "code": 7031,
+            "source": "deno-ts",
+            "message": "Binding element 'debugFlag' implicitly has an 'any' type."
+          }],
+          "only": [ "quickfix" ]
+        }
+      }),
     )
     .unwrap();
   assert!(maybe_err.is_none());
@@ -3763,12 +4811,13 @@ fn lsp_code_actions_deadlock() {
 
   read_diagnostics(&mut client);
 
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_completions() {
-  let mut client = init("initialize_params.json");
+  let mut client = LspClientBuilder::new().build();
+  client.initialize_default();
   did_open(
     &mut client,
     json!({
@@ -3787,10 +4836,7 @@ fn lsp_completions() {
         "textDocument": {
           "uri": "file:///a/file.ts"
         },
-        "position": {
-          "line": 0,
-          "character": 5
-        },
+        "position": { "line": 0, "character": 5 },
         "context": {
           "triggerKind": 2,
           "triggerCharacter": "."
@@ -3808,20 +4854,44 @@ fn lsp_completions() {
   let (maybe_res, maybe_err) = client
     .write_request(
       "completionItem/resolve",
-      load_fixture("completion_resolve_params.json"),
+      json!({
+        "label": "build",
+        "kind": 6,
+        "sortText": "1",
+        "insertTextFormat": 1,
+        "data": {
+          "tsc": {
+            "specifier": "file:///a/file.ts",
+            "position": 5,
+            "name": "build",
+            "useCodeSnippet": false
+          }
+        }
+      }),
     )
     .unwrap();
   assert!(maybe_err.is_none());
   assert_eq!(
     maybe_res,
-    Some(load_fixture("completion_resolve_response.json"))
+    Some(json!({
+      "label": "build",
+      "kind": 6,
+      "detail": "const Deno.build: {\n    target: string;\n    arch: \"x86_64\" | \"aarch64\";\n    os: \"darwin\" | \"linux\" | \"windows\" | \"freebsd\" | \"netbsd\" | \"aix\" | \"solaris\" | \"illumos\";\n    vendor: string;\n    env?: string | undefined;\n}",
+      "documentation": {
+        "kind": "markdown",
+        "value": "Information related to the build of the current Deno runtime.\n\nUsers are discouraged from code branching based on this information, as\nassumptions about what is available in what build environment might change\nover time. Developers should specifically sniff out the features they\nintend to use.\n\nThe intended use for the information is for logging and debugging purposes.\n\n*@category* - Runtime Environment"
+      },
+      "sortText": "1",
+      "insertTextFormat": 1
+    }))
   );
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_completions_private_fields() {
-  let mut client = init("initialize_params.json");
+  let mut client = LspClientBuilder::new().build();
+  client.initialize_default();
   did_open(
     &mut client,
     json!({
@@ -3840,10 +4910,7 @@ fn lsp_completions_private_fields() {
         "textDocument": {
           "uri": "file:///a/file.ts"
         },
-        "position": {
-          "line": 0,
-          "character": 57
-        },
+        "position": { "line": 0, "character": 57 },
         "context": {
           "triggerKind": 1
         }
@@ -3859,12 +4926,13 @@ fn lsp_completions_private_fields() {
   } else {
     panic!("unexpected response");
   }
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_completions_optional() {
-  let mut client = init("initialize_params.json");
+  let mut client = LspClientBuilder::new().build();
+  client.initialize_default();
   did_open(
     &mut client,
     json!({
@@ -3879,7 +4947,16 @@ fn lsp_completions_optional() {
   let (maybe_res, maybe_err) = client
     .write_request(
       "textDocument/completion",
-      load_fixture("completion_request_params_optional.json"),
+      json!({
+        "textDocument": {
+          "uri": "file:///a/file.ts"
+        },
+        "position": { "line": 8, "character": 4 },
+        "context": {
+          "triggerKind": 2,
+          "triggerCharacter": "."
+        }
+      }),
     )
     .unwrap();
   assert!(maybe_err.is_none());
@@ -3910,7 +4987,21 @@ fn lsp_completions_optional() {
   let (maybe_res, maybe_err) = client
     .write_request(
       "completionItem/resolve",
-      load_fixture("completion_resolve_params_optional.json"),
+      json!({
+        "label": "b?",
+        "kind": 5,
+        "sortText": "1",
+        "filterText": "b",
+        "insertText": "b",
+        "data": {
+          "tsc": {
+            "specifier": "file:///a/file.ts",
+            "position": 79,
+            "name": "b",
+            "useCodeSnippet": false
+          }
+        }
+      }),
     )
     .unwrap();
   assert!(maybe_err.is_none());
@@ -3929,12 +5020,13 @@ fn lsp_completions_optional() {
       "insertText": "b"
     }))
   );
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_completions_auto_import() {
-  let mut client = init("initialize_params.json");
+  let mut client = LspClientBuilder::new().build();
+  client.initialize_default();
   did_open(
     &mut client,
     json!({
@@ -3964,10 +5056,7 @@ fn lsp_completions_auto_import() {
         "textDocument": {
           "uri": "file:///a/file.ts"
         },
-        "position": {
-          "line": 2,
-          "character": 0,
-        },
+        "position": { "line": 2, "character": 0, },
         "context": {
           "triggerKind": 1,
         }
@@ -4028,14 +5117,8 @@ fn lsp_completions_auto_import() {
       "additionalTextEdits": [
         {
           "range": {
-            "start": {
-              "line": 0,
-              "character": 0
-            },
-            "end": {
-              "line": 0,
-              "character": 0
-            }
+            "start": { "line": 0, "character": 0 },
+            "end": { "line": 0, "character": 0 }
           },
           "newText": "import { foo } from \"./b.ts\";\n\n"
         }
@@ -4046,7 +5129,8 @@ fn lsp_completions_auto_import() {
 
 #[test]
 fn lsp_completions_snippet() {
-  let mut client = init("initialize_params.json");
+  let mut client = LspClientBuilder::new().build();
+  client.initialize_default();
   did_open(
     &mut client,
     json!({
@@ -4065,10 +5149,7 @@ fn lsp_completions_snippet() {
         "textDocument": {
           "uri": "file:///a/a.tsx"
         },
-        "position": {
-          "line": 5,
-          "character": 13,
-        },
+        "position": { "line": 5, "character": 13, },
         "context": {
           "triggerKind": 1,
         }
@@ -4159,7 +5240,13 @@ fn lsp_completions_snippet() {
 
 #[test]
 fn lsp_completions_no_snippet() {
-  let mut client = init("initialize_params_no_snippet.json");
+  let mut client = LspClientBuilder::new().build();
+  client.initialize(|builder| {
+    builder.with_capabilities(|c| {
+      let doc = c.text_document.as_mut().unwrap();
+      doc.completion = None;
+    });
+  });
   did_open(
     &mut client,
     json!({
@@ -4178,10 +5265,7 @@ fn lsp_completions_no_snippet() {
         "textDocument": {
           "uri": "file:///a/a.tsx"
         },
-        "position": {
-          "line": 5,
-          "character": 13,
-        },
+        "position": { "line": 5, "character": 13, },
         "context": {
           "triggerKind": 1,
         }
@@ -4225,8 +5309,9 @@ fn lsp_completions_no_snippet() {
 
 #[test]
 fn lsp_completions_npm() {
-  let _g = http_server();
-  let mut client = init("initialize_params.json");
+  let context = TestContextBuilder::new().use_http_server().build();
+  let mut client = context.new_lsp_command().build();
+  client.initialize_default();
   did_open(
     &mut client,
     json!({
@@ -4248,8 +5333,7 @@ fn lsp_completions_npm() {
         "uris": [
           {
             "uri": "npm:@denotest/cjs-default-export",
-          },
-          {
+          }, {
             "uri": "npm:chalk",
           }
         ]
@@ -4271,14 +5355,8 @@ fn lsp_completions_npm() {
         "contentChanges": [
           {
             "range": {
-              "start": {
-                "line": 2,
-                "character": 0
-              },
-              "end": {
-                "line": 2,
-                "character": 0
-              }
+              "start": { "line": 2, "character": 0 },
+              "end": { "line": 2, "character": 0 }
             },
             "text": "cjsDefault."
           }
@@ -4295,10 +5373,7 @@ fn lsp_completions_npm() {
         "textDocument": {
           "uri": "file:///a/file.ts"
         },
-        "position": {
-          "line": 2,
-          "character": 11
-        },
+        "position": { "line": 2, "character": 11 },
         "context": {
           "triggerKind": 2,
           "triggerCharacter": "."
@@ -4318,13 +5393,39 @@ fn lsp_completions_npm() {
   let (maybe_res, maybe_err) = client
     .write_request(
       "completionItem/resolve",
-      load_fixture("completions/npm/resolve_params.json"),
+      json!({
+        "label": "MyClass",
+        "kind": 6,
+        "sortText": "1",
+        "insertTextFormat": 1,
+        "data": {
+          "tsc": {
+            "specifier": "file:///a/file.ts",
+            "position": 69,
+            "name": "MyClass",
+            "useCodeSnippet": false
+          }
+        }
+      }),
     )
     .unwrap();
   assert!(maybe_err.is_none());
   assert_eq!(
     maybe_res,
-    Some(load_fixture("completions/npm/resolve_response.json"))
+    Some(json!({
+      "label": "MyClass",
+      "kind": 6,
+      "sortText": "1",
+      "insertTextFormat": 1,
+      "data": {
+        "tsc": {
+          "specifier": "file:///a/file.ts",
+          "position": 69,
+          "name": "MyClass",
+          "useCodeSnippet": false
+        }
+      }
+    }))
   );
 
   // now check chalk, which is esm
@@ -4339,14 +5440,8 @@ fn lsp_completions_npm() {
         "contentChanges": [
           {
             "range": {
-              "start": {
-                "line": 2,
-                "character": 0
-              },
-              "end": {
-                "line": 2,
-                "character": 11
-              }
+              "start": { "line": 2, "character": 0 },
+              "end": { "line": 2, "character": 11 }
             },
             "text": "chalk."
           }
@@ -4363,10 +5458,7 @@ fn lsp_completions_npm() {
         "textDocument": {
           "uri": "file:///a/file.ts"
         },
-        "position": {
-          "line": 2,
-          "character": 6
-        },
+        "position": { "line": 2, "character": 6 },
         "context": {
           "triggerKind": 2,
           "triggerCharacter": "."
@@ -4383,13 +5475,14 @@ fn lsp_completions_npm() {
     panic!("unexpected response");
   }
 
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_npm_specifier_unopened_file() {
-  let _g = http_server();
-  let mut client = init("initialize_params.json");
+  let context = TestContextBuilder::new().use_http_server().build();
+  let mut client = context.new_lsp_command().build();
+  client.initialize_default();
 
   // create other.ts, which re-exports an npm specifier
   client.deno_dir().write(
@@ -4444,14 +5537,8 @@ fn lsp_npm_specifier_unopened_file() {
         "contentChanges": [
           {
             "range": {
-              "start": {
-                "line": 2,
-                "character": 0
-              },
-              "end": {
-                "line": 2,
-                "character": 0
-              }
+              "start": { "line": 2, "character": 0 },
+              "end": { "line": 2, "character": 0 }
             },
             "text": "chalk."
           }
@@ -4469,10 +5556,7 @@ fn lsp_npm_specifier_unopened_file() {
         "textDocument": {
           "uri": main_url
         },
-        "position": {
-          "line": 2,
-          "character": 6
-        },
+        "position": { "line": 2, "character": 6 },
         "context": {
           "triggerKind": 2,
           "triggerCharacter": "."
@@ -4492,8 +5576,9 @@ fn lsp_npm_specifier_unopened_file() {
 
 #[test]
 fn lsp_completions_node_specifier() {
-  let _g = http_server();
-  let mut client = init("initialize_params.json");
+  let context = TestContextBuilder::new().use_http_server().build();
+  let mut client = context.new_lsp_command().build();
+  client.initialize_default();
   let diagnostics = CollectedDiagnostics(did_open(
     &mut client,
     json!({
@@ -4578,9 +5663,7 @@ fn lsp_completions_node_specifier() {
         },
         "context": {
           "diagnostics": json!(diagnostics),
-          "only": [
-            "quickfix"
-          ]
+          "only": ["quickfix"]
         }
       }),
     )
@@ -4737,13 +5820,16 @@ fn lsp_completions_node_specifier() {
     panic!("unexpected response");
   }
 
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_completions_registry() {
-  let _g = http_server();
-  let mut client = init("initialize_params_registry.json");
+  let context = TestContextBuilder::new().use_http_server().build();
+  let mut client = context.new_lsp_command().build();
+  client.initialize(|builder| {
+    builder.add_test_server_suggestions();
+  });
   did_open(
     &mut client,
     json!({
@@ -4762,10 +5848,7 @@ fn lsp_completions_registry() {
         "textDocument": {
           "uri": "file:///a/file.ts"
         },
-        "position": {
-          "line": 0,
-          "character": 46
-        },
+        "position": { "line": 0, "character": 46 },
         "context": {
           "triggerKind": 2,
           "triggerCharacter": "@"
@@ -4783,21 +5866,50 @@ fn lsp_completions_registry() {
   let (maybe_res, maybe_err) = client
     .write_request(
       "completionItem/resolve",
-      load_fixture("completion_resolve_params_registry.json"),
+      json!({
+        "label": "v2.0.0",
+        "kind": 19,
+        "detail": "(version)",
+        "sortText": "0000000003",
+        "filterText": "http://localhost:4545/x/a@v2.0.0",
+        "textEdit": {
+          "range": {
+            "start": { "line": 0, "character": 20 },
+            "end": { "line": 0, "character": 46 }
+          },
+          "newText": "http://localhost:4545/x/a@v2.0.0"
+        }
+      }),
     )
     .unwrap();
   assert!(maybe_err.is_none());
   assert_eq!(
     maybe_res,
-    Some(load_fixture("completion_resolve_response_registry.json"))
+    Some(json!({
+      "label": "v2.0.0",
+      "kind": 19,
+      "detail": "(version)",
+      "sortText": "0000000003",
+      "filterText": "http://localhost:4545/x/a@v2.0.0",
+      "textEdit": {
+        "range": {
+          "start": { "line": 0, "character": 20 },
+          "end": { "line": 0, "character": 46 }
+        },
+        "newText": "http://localhost:4545/x/a@v2.0.0"
+      }
+    }))
   );
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_completions_registry_empty() {
-  let _g = http_server();
-  let mut client = init("initialize_params_registry.json");
+  let context = TestContextBuilder::new().use_http_server().build();
+  let mut client = context.new_lsp_command().build();
+  client.initialize(|builder| {
+    builder.add_test_server_suggestions();
+  });
   did_open(
     &mut client,
     json!({
@@ -4816,10 +5928,7 @@ fn lsp_completions_registry_empty() {
         "textDocument": {
           "uri": "file:///a/file.ts"
         },
-        "position": {
-          "line": 0,
-          "character": 20
-        },
+        "position": { "line": 0, "character": 20 },
         "context": {
           "triggerKind": 2,
           "triggerCharacter": "\""
@@ -4830,15 +5939,46 @@ fn lsp_completions_registry_empty() {
   assert!(maybe_err.is_none());
   assert_eq!(
     maybe_res,
-    Some(load_fixture("completion_request_response_empty.json"))
+    Some(json!({
+      "isIncomplete": false,
+      "items": [{
+        "label": ".",
+        "kind": 19,
+        "detail": "(local)",
+        "sortText": "1",
+        "insertText": ".",
+        "commitCharacters": ["\"", "'"]
+      }, {
+        "label": "..",
+        "kind": 19,
+        "detail": "(local)",
+        "sortText": "1",
+        "insertText": "..",
+        "commitCharacters": ["\"", "'" ]
+      }, {
+        "label": "http://localhost:4545",
+        "kind": 19,
+        "detail": "(registry)",
+        "sortText": "2",
+        "textEdit": {
+          "range": {
+            "start": { "line": 0, "character": 20 },
+            "end": { "line": 0, "character": 20 }
+          },
+          "newText": "http://localhost:4545"
+        },
+        "commitCharacters": ["\"", "'", "/"]
+      }]
+    }))
   );
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_auto_discover_registry() {
-  let _g = http_server();
-  let mut client = init("initialize_params.json");
+  let context = TestContextBuilder::new().use_http_server().build();
+  let mut client = context.new_lsp_command().build();
+  client.initialize_default();
   did_open(
     &mut client,
     json!({
@@ -4857,10 +5997,7 @@ fn lsp_auto_discover_registry() {
         "textDocument": {
           "uri": "file:///a/file.ts"
         },
-        "position": {
-          "line": 0,
-          "character": 46
-        },
+        "position": { "line": 0, "character": 46 },
         "context": {
           "triggerKind": 2,
           "triggerCharacter": "@"
@@ -4879,31 +6016,19 @@ fn lsp_auto_discover_registry() {
       "suggestions": true,
     }))
   );
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_cache_location() {
-  let _g = http_server();
-  let temp_dir = TempDir::new();
-  let mut params: lsp::InitializeParams =
-    serde_json::from_value(load_fixture("initialize_params_registry.json"))
-      .unwrap();
-
-  params.root_uri = Some(Url::from_file_path(temp_dir.path()).unwrap());
-  if let Some(Value::Object(mut map)) = params.initialization_options {
-    map.insert("cache".to_string(), json!(".cache"));
-    params.initialization_options = Some(Value::Object(map));
-  }
+  let context = TestContextBuilder::new().use_http_server().build();
+  let temp_dir = context.deno_dir();
+  let mut client = context.new_lsp_command().build();
+  client.initialize(|builder| {
+    builder.set_cache(".cache").add_test_server_suggestions();
+  });
 
-  let deno_exe = deno_exe_path();
-  let mut client = LspClient::new(&deno_exe, false).unwrap();
-  client
-    .write_request::<_, _, Value>("initialize", params)
-    .unwrap();
-  client.write_notification("initialized", json!({})).unwrap();
   let mut session = TestSession::from_client(client);
-
   session.did_open(json!({
     "textDocument": {
       "uri": "file:///a/file_01.ts",
@@ -4913,7 +6038,14 @@ fn lsp_cache_location() {
     }
   }));
   let diagnostics =
-    session.did_open(load_fixture("did_open_params_import_hover.json"));
+    session.did_open(json!({
+      "textDocument": {
+        "uri": "file:///a/file.ts",
+        "languageId": "typescript",
+        "version": 1,
+        "text": "import * as a from \"http://127.0.0.1:4545/xTypeScriptTypes.js\";\n// @deno-types=\"http://127.0.0.1:4545/type_definitions/foo.d.ts\"\nimport * as b from \"http://127.0.0.1:4545/type_definitions/foo.js\";\nimport * as c from \"http://127.0.0.1:4545/subdir/type_reference.js\";\nimport * as d from \"http://127.0.0.1:4545/subdir/mod1.ts\";\nimport * as e from \"data:application/typescript;base64,ZXhwb3J0IGNvbnN0IGEgPSAiYSI7CgpleHBvcnQgZW51bSBBIHsKICBBLAogIEIsCiAgQywKfQo=\";\nimport * as f from \"./file_01.ts\";\nimport * as g from \"http://localhost:4545/x/a/mod.ts\";\n\nconsole.log(a, b, c, d, e, f, g);\n"
+      }
+    }));
   assert_eq!(diagnostics.viewed().len(), 7);
   let (maybe_res, maybe_err) = session
     .client
@@ -4937,10 +6069,7 @@ fn lsp_cache_location() {
         "textDocument": {
           "uri": "file:///a/file.ts",
         },
-        "position": {
-          "line": 0,
-          "character": 28
-        }
+        "position": { "line": 0, "character": 28 }
       }),
     )
     .unwrap();
@@ -4953,14 +6082,8 @@ fn lsp_cache_location() {
         "value": "**Resolved Dependency**\n\n**Code**: http&#8203;://127.0.0.1:4545/xTypeScriptTypes.js\n\n**Types**: http&#8203;://127.0.0.1:4545/xTypeScriptTypes.d.ts\n"
       },
       "range": {
-        "start": {
-          "line": 0,
-          "character": 19
-        },
-        "end":{
-          "line": 0,
-          "character": 62
-        }
+        "start": { "line": 0, "character": 19 },
+        "end": { "line": 0, "character": 62 }
       }
     }))
   );
@@ -4972,10 +6095,7 @@ fn lsp_cache_location() {
         "textDocument": {
           "uri": "file:///a/file.ts",
         },
-        "position": {
-          "line": 7,
-          "character": 28
-        }
+        "position": { "line": 7, "character": 28 }
       }),
     )
     .unwrap();
@@ -4988,14 +6108,8 @@ fn lsp_cache_location() {
         "value": "**Resolved Dependency**\n\n**Code**: http&#8203;://localhost:4545/x/a/mod.ts\n\n\n---\n\n**a**\n\nmod.ts"
       },
       "range": {
-        "start": {
-          "line": 7,
-          "character": 19
-        },
-        "end": {
-          "line": 7,
-          "character": 53
-        }
+        "start": { "line": 7, "character": 19 },
+        "end": { "line": 7, "character": 53 }
       }
     }))
   );
@@ -5010,19 +6124,17 @@ fn lsp_cache_location() {
 /// and cache files.
 #[test]
 fn lsp_tls_cert() {
-  let _g = http_server();
-  let mut params: lsp::InitializeParams =
-    serde_json::from_value(load_fixture("initialize_params_tls_cert.json"))
-      .unwrap();
-
-  params.root_uri = Some(Url::from_file_path(testdata_path()).unwrap());
+  let context = TestContextBuilder::new().use_http_server().build();
+  let mut client = context.new_lsp_command().build();
+  client.initialize(|builder| {
+    builder
+      .set_suggest_imports_hosts(vec![
+        ("http://localhost:4545/".to_string(), true),
+        ("https://localhost:5545/".to_string(), true),
+      ])
+      .set_tls_certificate("");
+  });
 
-  let deno_exe = deno_exe_path();
-  let mut client = LspClient::new(&deno_exe, false).unwrap();
-  client
-    .write_request::<_, _, Value>("initialize", params)
-    .unwrap();
-  client.write_notification("initialized", json!({})).unwrap();
   let mut session = TestSession::from_client(client);
 
   session.did_open(json!({
@@ -5033,8 +6145,14 @@ fn lsp_tls_cert() {
       "text": "export const a = \"a\";\n",
     }
   }));
-  let diagnostics =
-    session.did_open(load_fixture("did_open_params_tls_cert.json"));
+  let diagnostics = session.did_open(json!({
+    "textDocument": {
+      "uri": "file:///a/file.ts",
+      "languageId": "typescript",
+      "version": 1,
+      "text": "import * as a from \"https://localhost:5545/xTypeScriptTypes.js\";\n// @deno-types=\"https://localhost:5545/type_definitions/foo.d.ts\"\nimport * as b from \"https://localhost:5545/type_definitions/foo.js\";\nimport * as c from \"https://localhost:5545/subdir/type_reference.js\";\nimport * as d from \"https://localhost:5545/subdir/mod1.ts\";\nimport * as e from \"data:application/typescript;base64,ZXhwb3J0IGNvbnN0IGEgPSAiYSI7CgpleHBvcnQgZW51bSBBIHsKICBBLAogIEIsCiAgQywKfQo=\";\nimport * as f from \"./file_01.ts\";\nimport * as g from \"http://localhost:4545/x/a/mod.ts\";\n\nconsole.log(a, b, c, d, e, f, g);\n"
+    }
+  }));
   let diagnostics = diagnostics.viewed();
   assert_eq!(diagnostics.len(), 7);
   let (maybe_res, maybe_err) = session
@@ -5059,10 +6177,7 @@ fn lsp_tls_cert() {
         "textDocument": {
           "uri": "file:///a/file.ts",
         },
-        "position": {
-          "line": 0,
-          "character": 28
-        }
+        "position": { "line": 0, "character": 28 }
       }),
     )
     .unwrap();
@@ -5075,14 +6190,8 @@ fn lsp_tls_cert() {
         "value": "**Resolved Dependency**\n\n**Code**: https&#8203;://localhost:5545/xTypeScriptTypes.js\n"
       },
       "range": {
-        "start": {
-          "line": 0,
-          "character": 19
-        },
-        "end":{
-          "line": 0,
-          "character": 63
-        }
+        "start": { "line": 0, "character": 19 },
+        "end": { "line": 0, "character": 63 }
       }
     }))
   );
@@ -5094,10 +6203,7 @@ fn lsp_tls_cert() {
         "textDocument": {
           "uri": "file:///a/file.ts",
         },
-        "position": {
-          "line": 7,
-          "character": 28
-        }
+        "position": { "line": 7, "character": 28 }
       }),
     )
     .unwrap();
@@ -5110,14 +6216,8 @@ fn lsp_tls_cert() {
         "value": "**Resolved Dependency**\n\n**Code**: http&#8203;://localhost:4545/x/a/mod.ts\n\n\n---\n\n**a**\n\nmod.ts"
       },
       "range": {
-        "start": {
-          "line": 7,
-          "character": 19
-        },
-        "end": {
-          "line": 7,
-          "character": 53
-        }
+        "start": { "line": 7, "character": 19 },
+        "end": { "line": 7, "character": 53 }
       }
     }))
   );
@@ -5126,8 +6226,9 @@ fn lsp_tls_cert() {
 
 #[test]
 fn lsp_diagnostics_warn_redirect() {
-  let _g = http_server();
-  let mut client = init("initialize_params.json");
+  let context = TestContextBuilder::new().use_http_server().build();
+  let mut client = context.new_lsp_command().build();
+  client.initialize_default();
   did_open(
     &mut client,
     json!({
@@ -5201,13 +6302,14 @@ fn lsp_diagnostics_warn_redirect() {
       version: Some(1),
     }
   );
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_redirect_quick_fix() {
-  let _g = http_server();
-  let mut client = init("initialize_params.json");
+  let context = TestContextBuilder::new().use_http_server().build();
+  let mut client = context.new_lsp_command().build();
+  client.initialize_default();
   did_open(
     &mut client,
     json!({
@@ -5247,20 +6349,12 @@ fn lsp_redirect_quick_fix() {
           "uri": "file:///a/file.ts"
         },
         "range": {
-          "start": {
-            "line": 0,
-            "character": 19
-          },
-          "end": {
-            "line": 0,
-            "character": 60
-          }
+          "start": { "line": 0, "character": 19 },
+          "end": { "line": 0, "character": 60 }
         },
         "context": {
           "diagnostics": diagnostics,
-          "only": [
-            "quickfix"
-          ]
+          "only": ["quickfix"]
         }
       })),
     )
@@ -5268,14 +6362,47 @@ fn lsp_redirect_quick_fix() {
   assert!(maybe_err.is_none());
   assert_eq!(
     maybe_res,
-    Some(load_fixture("code_action_redirect_response.json"))
+    Some(json!([{
+      "title": "Update specifier to its redirected specifier.",
+      "kind": "quickfix",
+      "diagnostics": [
+        {
+          "range": {
+            "start": { "line": 0, "character": 19 },
+            "end": { "line": 0, "character": 60 }
+          },
+          "severity": 3,
+          "code": "redirect",
+          "source": "deno",
+          "message": "The import of \"http://127.0.0.1:4545/x_deno_warning.js\" was redirected to \"http://127.0.0.1:4545/lsp/x_deno_warning_redirect.js\".",
+          "data": {
+            "specifier": "http://127.0.0.1:4545/x_deno_warning.js",
+            "redirect": "http://127.0.0.1:4545/lsp/x_deno_warning_redirect.js"
+          }
+        }
+      ],
+      "edit": {
+        "changes": {
+          "file:///a/file.ts": [
+            {
+              "range": {
+                "start": { "line": 0, "character": 19 },
+                "end": { "line": 0, "character": 60 }
+              },
+              "newText": "\"http://127.0.0.1:4545/lsp/x_deno_warning_redirect.js\""
+            }
+          ]
+        }
+      }
+    }]))
   );
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_diagnostics_deprecated() {
-  let mut client = init("initialize_params.json");
+  let mut client = LspClientBuilder::new().build();
+  client.initialize_default();
   let diagnostics = did_open(
     &mut client,
     json!({
@@ -5294,50 +6421,48 @@ fn lsp_diagnostics_deprecated() {
         "uri": "file:///a/file.ts",
         "diagnostics": [],
         "version": 1
-      },
-      {
+      }, {
         "uri": "file:///a/file.ts",
         "diagnostics": [],
         "version": 1
-      },
-      {
+      }, {
         "uri": "file:///a/file.ts",
         "diagnostics": [
           {
             "range": {
-              "start": {
-                "line": 3,
-                "character": 0
-              },
-              "end": {
-                "line": 3,
-                "character": 1
-              }
+              "start": { "line": 3, "character": 0 },
+              "end": { "line": 3, "character": 1 }
             },
             "severity": 4,
             "code": 6385,
             "source": "deno-ts",
             "message": "'a' is deprecated.",
             "relatedInformation": [],
-            "tags": [
-              2
-            ]
+            "tags": [2]
           }
         ],
         "version": 1
       }
     ])
   );
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_diagnostics_deno_types() {
-  let mut client = init("initialize_params.json");
+  let mut client = LspClientBuilder::new().build();
+  client.initialize_default();
   client
     .write_notification(
       "textDocument/didOpen",
-      load_fixture("did_open_params_deno_types.json"),
+      json!({
+        "textDocument": {
+          "uri": "file:///a/file.ts",
+          "languageId": "typescript",
+          "version": 1,
+          "text": "/// <reference types=\"https://example.com/a/b.d.ts\" />\n/// <reference path=\"https://example.com/a/c.ts\"\n\n// @deno-types=https://example.com/a/d.d.ts\nimport * as d from \"https://example.com/a/d.js\";\n\n// @deno-types=\"https://example.com/a/e.d.ts\"\nimport * as e from \"https://example.com/a/e.js\";\n\nconsole.log(d, e);\n"
+        }
+      }),
     )
     .unwrap();
   let (id, method, _) = client.read_request::<Value>().unwrap();
@@ -5359,12 +6484,14 @@ fn lsp_diagnostics_deno_types() {
   assert!(maybe_err.is_none());
   let diagnostics = read_diagnostics(&mut client);
   assert_eq!(diagnostics.viewed().len(), 5);
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_diagnostics_refresh_dependents() {
-  let mut session = TestSession::from_file("initialize_params.json");
+  let mut client = LspClientBuilder::new().build();
+  client.initialize_default();
+  let mut session = TestSession::from_client(client);
   session.did_open(json!({
     "textDocument": {
       "uri": "file:///a/file_00.ts",
@@ -5396,14 +6523,8 @@ fn lsp_diagnostics_refresh_dependents() {
       "diagnostics": [
         {
           "range": {
-            "start": {
-              "line": 0,
-              "character": 12
-            },
-            "end": {
-              "line": 0,
-              "character": 13
-            }
+            "start": { "line": 0, "character": 12 },
+            "end": { "line": 0, "character": 13 }
           },
           "severity": 1,
           "code": 2305,
@@ -5428,14 +6549,8 @@ fn lsp_diagnostics_refresh_dependents() {
         "contentChanges": [
           {
             "range": {
-              "start": {
-                "line": 1,
-                "character": 0
-              },
-              "end": {
-                "line": 1,
-                "character": 0
-              }
+              "start": { "line": 1, "character": 0 },
+              "end": { "line": 1, "character": 0 }
             },
             "text": "export const b = \"b\";\n"
           }
@@ -5466,7 +6581,8 @@ struct PerformanceAverages {
 
 #[test]
 fn lsp_performance() {
-  let mut client = init("initialize_params.json");
+  let mut client = LspClientBuilder::new().build();
+  client.initialize_default();
   did_open(
     &mut client,
     json!({
@@ -5485,10 +6601,7 @@ fn lsp_performance() {
         "textDocument": {
           "uri": "file:///a/file.ts"
         },
-        "position": {
-          "line": 0,
-          "character": 19
-        }
+        "position": { "line": 0, "character": 19 }
       }),
     )
     .unwrap();
@@ -5503,12 +6616,13 @@ fn lsp_performance() {
   } else {
     panic!("unexpected result");
   }
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_format_no_changes() {
-  let mut client = init("initialize_params.json");
+  let mut client = LspClientBuilder::new().build();
+  client.initialize_default();
   did_open(
     &mut client,
     json!({
@@ -5537,12 +6651,13 @@ fn lsp_format_no_changes() {
   assert!(maybe_err.is_none());
   assert_eq!(maybe_res, Some(json!(null)));
   client.assert_no_notification("window/showMessage");
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_format_error() {
-  let mut client = init("initialize_params.json");
+  let mut client = LspClientBuilder::new().build();
+  client.initialize_default();
   did_open(
     &mut client,
     json!({
@@ -5570,12 +6685,13 @@ fn lsp_format_error() {
     .unwrap();
   assert!(maybe_err.is_none());
   assert_eq!(maybe_res, Some(json!(null)));
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_format_mbc() {
-  let mut client = init("initialize_params.json");
+  let mut client = LspClientBuilder::new().build();
+  client.initialize_default();
   did_open(
     &mut client,
     json!({
@@ -5604,36 +6720,64 @@ fn lsp_format_mbc() {
   assert!(maybe_err.is_none());
   assert_eq!(
     maybe_res,
-    Some(json!(load_fixture("formatting_mbc_response.json")))
+    Some(json!([{
+      "range": {
+        "start": { "line": 0, "character": 12 },
+        "end": { "line": 0, "character": 13 }
+      },
+      "newText": "\""
+    }, {
+      "range": {
+        "start": { "line": 0, "character": 21 },
+        "end": { "line": 0, "character": 22 }
+      },
+      "newText": "\";"
+    }, {
+      "range": {
+        "start": { "line": 1, "character": 12 },
+        "end": { "line": 1, "character": 13 }
+      },
+      "newText": "\""
+    }, {
+      "range": {
+        "start": { "line": 1, "character": 23 },
+        "end": { "line": 1, "character": 25 }
+      },
+      "newText": "\");"
+    }]))
   );
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_format_exclude_with_config() {
-  let temp_dir = TempDir::new();
-  let mut params: lsp::InitializeParams =
-    serde_json::from_value(load_fixture("initialize_params.json")).unwrap();
-  let deno_fmt_jsonc =
-    serde_json::to_vec_pretty(&load_fixture("deno.fmt.exclude.jsonc")).unwrap();
-  fs::write(temp_dir.path().join("deno.fmt.jsonc"), deno_fmt_jsonc).unwrap();
-
-  params.root_uri = Some(Url::from_file_path(temp_dir.path()).unwrap());
-  if let Some(Value::Object(mut map)) = params.initialization_options {
-    map.insert("config".to_string(), json!("./deno.fmt.jsonc"));
-    params.initialization_options = Some(Value::Object(map));
-  }
+  let context = TestContextBuilder::new().build();
+  let temp_dir = context.deno_dir();
 
-  let deno_exe = deno_exe_path();
-  let mut client = LspClient::new(&deno_exe, false).unwrap();
-  client
-    .write_request::<_, _, Value>("initialize", params)
-    .unwrap();
+  temp_dir.write(
+    "deno.fmt.jsonc",
+    r#"{
+    "fmt": {
+      "files": {
+        "exclude": ["ignored.ts"]
+      },
+      "options": {
+        "useTabs": true,
+        "lineWidth": 40,
+        "indentWidth": 8,
+        "singleQuote": true,
+        "proseWrap": "always"
+      }
+    }
+  }"#,
+  );
 
-  let file_uri =
-    ModuleSpecifier::from_file_path(temp_dir.path().join("ignored.ts"))
-      .unwrap()
-      .to_string();
+  let mut client = context.new_lsp_command().build();
+  client.initialize(|builder| {
+    builder.set_config("./deno.fmt.jsonc");
+  });
+
+  let file_uri = temp_dir.uri().join("ignored.ts").unwrap();
   did_open(
     &mut client,
     json!({
@@ -5661,31 +6805,38 @@ fn lsp_format_exclude_with_config() {
     .unwrap();
   assert!(maybe_err.is_none());
   assert_eq!(maybe_res, Some(json!(null)));
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_format_exclude_default_config() {
-  let temp_dir = TempDir::new();
-  let workspace_root = temp_dir.path().canonicalize().unwrap();
-  let mut params: lsp::InitializeParams =
-    serde_json::from_value(load_fixture("initialize_params.json")).unwrap();
-  let deno_jsonc =
-    serde_json::to_vec_pretty(&load_fixture("deno.fmt.exclude.jsonc")).unwrap();
-  fs::write(workspace_root.join("deno.jsonc"), deno_jsonc).unwrap();
-
-  params.root_uri = Some(Url::from_file_path(workspace_root.clone()).unwrap());
-
-  let deno_exe = deno_exe_path();
-  let mut client = LspClient::new(&deno_exe, false).unwrap();
-  client
-    .write_request::<_, _, Value>("initialize", params)
-    .unwrap();
+  let context = TestContextBuilder::new().build();
+  let temp_dir = context.deno_dir();
 
-  let file_uri =
-    ModuleSpecifier::from_file_path(workspace_root.join("ignored.ts"))
-      .unwrap()
-      .to_string();
+  temp_dir.write(
+    "deno.fmt.jsonc",
+    r#"{
+    "fmt": {
+      "files": {
+        "exclude": ["ignored.ts"]
+      },
+      "options": {
+        "useTabs": true,
+        "lineWidth": 40,
+        "indentWidth": 8,
+        "singleQuote": true,
+        "proseWrap": "always"
+      }
+    }
+  }"#,
+  );
+
+  let mut client = context.new_lsp_command().build();
+  client.initialize(|builder| {
+    builder.set_config("./deno.fmt.jsonc");
+  });
+
+  let file_uri = temp_dir.uri().join("ignored.ts").unwrap();
   did_open(
     &mut client,
     json!({
@@ -5713,12 +6864,13 @@ fn lsp_format_exclude_default_config() {
     .unwrap();
   assert!(maybe_err.is_none());
   assert_eq!(maybe_res, Some(json!(null)));
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_format_json() {
-  let mut client = init("initialize_params.json");
+  let mut client = LspClientBuilder::new().build();
+  client.initialize_default();
   client
     .write_notification(
       "textDocument/didOpen",
@@ -5756,25 +6908,17 @@ fn lsp_format_json() {
     Some(json!([
       {
         "range": {
-          "start": {
-            "line": 0,
-            "character": 1
-          },
-          "end": {
-            "line": 0,
-            "character": 1
-          }
+          "start": { "line": 0, "character": 1 },
+          "end": { "line": 0, "character": 1 }
         },
         "newText": " "
-      },
-      {
+      }, {
         "range": {
           "start": { "line": 0, "character": 7 },
           "end": { "line": 0, "character": 7 }
         },
         "newText": " "
-      },
-      {
+      }, {
         "range": {
           "start": { "line": 0, "character": 14 },
           "end": { "line": 0, "character": 15 }
@@ -5783,12 +6927,13 @@ fn lsp_format_json() {
       }
     ]))
   );
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_json_no_diagnostics() {
-  let mut client = init("initialize_params.json");
+  let mut client = LspClientBuilder::new().build();
+  client.initialize_default();
   client
     .write_notification(
       "textDocument/didOpen",
@@ -5823,22 +6968,20 @@ fn lsp_json_no_diagnostics() {
         "textDocument": {
           "uri": "file:///a/file.json"
         },
-        "position": {
-          "line": 0,
-          "character": 3
-        }
+        "position": { "line": 0, "character": 3 }
       }),
     )
     .unwrap();
   assert!(maybe_err.is_none());
   assert_eq!(maybe_res, Some(json!(null)));
 
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_format_markdown() {
-  let mut client = init("initialize_params.json");
+  let mut client = LspClientBuilder::new().build();
+  client.initialize_default();
   client
     .write_notification(
       "textDocument/didOpen",
@@ -5878,8 +7021,7 @@ fn lsp_format_markdown() {
           "end": { "line": 0, "character": 3 }
         },
         "newText": ""
-      },
-      {
+      }, {
         "range": {
           "start": { "line": 0, "character": 15 },
           "end": { "line": 0, "character": 15 }
@@ -5888,29 +7030,33 @@ fn lsp_format_markdown() {
       }
     ]))
   );
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_format_with_config() {
-  let temp_dir = TempDir::new();
-  let mut params: lsp::InitializeParams =
-    serde_json::from_value(load_fixture("initialize_params.json")).unwrap();
-  let deno_fmt_jsonc =
-    serde_json::to_vec_pretty(&load_fixture("deno.fmt.jsonc")).unwrap();
-  fs::write(temp_dir.path().join("deno.fmt.jsonc"), deno_fmt_jsonc).unwrap();
-
-  params.root_uri = Some(Url::from_file_path(temp_dir.path()).unwrap());
-  if let Some(Value::Object(mut map)) = params.initialization_options {
-    map.insert("config".to_string(), json!("./deno.fmt.jsonc"));
-    params.initialization_options = Some(Value::Object(map));
+  let context = TestContextBuilder::new().build();
+  let temp_dir = context.deno_dir();
+  temp_dir.write(
+    "deno.fmt.jsonc",
+    r#"{
+    "fmt": {
+      "options": {
+        "useTabs": true,
+        "lineWidth": 40,
+        "indentWidth": 8,
+        "singleQuote": true,
+        "proseWrap": "always"
+      }
+    }
   }
+  "#,
+  );
 
-  let deno_exe = deno_exe_path();
-  let mut client = LspClient::new(&deno_exe, false).unwrap();
-  client
-    .write_request::<_, _, Value>("initialize", params)
-    .unwrap();
+  let mut client = context.new_lsp_command().build();
+  client.initialize(|builder| {
+    builder.set_config("./deno.fmt.jsonc");
+  });
 
   client
     .write_notification(
@@ -5947,116 +7093,62 @@ fn lsp_format_with_config() {
     maybe_res,
     Some(json!([{
         "range": {
-          "start": {
-            "line": 1,
-            "character": 0
-          },
-          "end": {
-            "line": 1,
-            "character": 0
-          }
+          "start": { "line": 1, "character": 0 },
+          "end": { "line": 1, "character": 0 }
         },
         "newText": "\t"
-      },
-      {
+      }, {
         "range": {
-          "start": {
-            "line": 1,
-            "character": 23
-          },
-          "end": {
-            "line": 1,
-            "character": 24
-          }
+          "start": { "line": 1, "character": 23 },
+          "end": { "line": 1, "character": 24 }
         },
         "newText": "\n\t\t'"
-      },
-      {
+      }, {
         "range": {
-          "start": {
-            "line": 1,
-            "character": 73
-          },
-          "end": {
-            "line": 1,
-            "character": 74
-          }
+          "start": { "line": 1, "character": 73 },
+          "end": { "line": 1, "character": 74 }
         },
         "newText": "',\n\t"
-      },
-      {
+      }, {
         "range": {
-          "start": {
-            "line": 2,
-            "character": 0
-          },
-          "end": {
-            "line": 2,
-            "character": 0
-          }
+          "start": { "line": 2, "character": 0 },
+          "end": { "line": 2, "character": 0 }
         },
         "newText": "\t"
-      },
-      {
+      }, {
         "range": {
-          "start": {
-            "line": 3,
-            "character": 0
-          },
-          "end": {
-            "line": 3,
-            "character": 0
-          }
+          "start": { "line": 3, "character": 0 },
+          "end": { "line": 3, "character": 0 }
         },
         "newText": "\t"
-      },
-      {
+      }, {
         "range": {
-          "start": {
-            "line": 3,
-            "character": 12
-          },
-          "end": {
-            "line": 3,
-            "character": 13
-          }
+          "start": { "line": 3, "character": 12 },
+          "end": { "line": 3, "character": 13 }
         },
         "newText": "'"
-      },
-      {
+      }, {
         "range": {
-          "start": {
-            "line": 3,
-            "character": 22
-          },
-          "end": {
-            "line": 3,
-            "character": 24
-          }
+          "start": { "line": 3, "character": 22 },
+          "end": { "line": 3, "character": 24 }
         },
         "newText": "');"
-      },
-      {
+      }, {
         "range": {
-          "start": {
-            "line": 4,
-            "character": 1
-          },
-          "end": {
-            "line": 4,
-            "character": 1
-          }
+          "start": { "line": 4, "character": 1 },
+          "end": { "line": 4, "character": 1 }
         },
         "newText": "\n"
       }]
     ))
   );
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_markdown_no_diagnostics() {
-  let mut client = init("initialize_params.json");
+  let mut client = LspClientBuilder::new().build();
+  client.initialize_default();
   client
     .write_notification(
       "textDocument/didOpen",
@@ -6091,23 +7183,21 @@ fn lsp_markdown_no_diagnostics() {
         "textDocument": {
           "uri": "file:///a/file.md"
         },
-        "position": {
-          "line": 0,
-          "character": 3
-        }
+        "position": { "line": 0, "character": 3 }
       }),
     )
     .unwrap();
   assert!(maybe_err.is_none());
   assert_eq!(maybe_res, Some(json!(null)));
 
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_configuration_did_change() {
-  let _g = http_server();
-  let mut client = init("initialize_params_did_config_change.json");
+  let context = TestContextBuilder::new().use_http_server().build();
+  let mut client = context.new_lsp_command().build();
+  client.initialize_default();
   did_open(
     &mut client,
     json!({
@@ -6162,10 +7252,7 @@ fn lsp_configuration_did_change() {
         "textDocument": {
           "uri": "file:///a/file.ts"
         },
-        "position": {
-          "line": 0,
-          "character": 46
-        },
+        "position": { "line": 0, "character": 46 },
         "context": {
           "triggerKind": 2,
           "triggerCharacter": "@"
@@ -6183,20 +7270,47 @@ fn lsp_configuration_did_change() {
   let (maybe_res, maybe_err) = client
     .write_request(
       "completionItem/resolve",
-      load_fixture("completion_resolve_params_registry.json"),
+      json!({
+        "label": "v2.0.0",
+        "kind": 19,
+        "detail": "(version)",
+        "sortText": "0000000003",
+        "filterText": "http://localhost:4545/x/a@v2.0.0",
+        "textEdit": {
+          "range": {
+            "start": { "line": 0, "character": 20 },
+            "end": { "line": 0, "character": 46 }
+          },
+          "newText": "http://localhost:4545/x/a@v2.0.0"
+        }
+      }),
     )
     .unwrap();
   assert!(maybe_err.is_none());
   assert_eq!(
     maybe_res,
-    Some(load_fixture("completion_resolve_response_registry.json"))
+    Some(json!({
+      "label": "v2.0.0",
+      "kind": 19,
+      "detail": "(version)",
+      "sortText": "0000000003",
+      "filterText": "http://localhost:4545/x/a@v2.0.0",
+      "textEdit": {
+        "range": {
+          "start": { "line": 0, "character": 20 },
+          "end": { "line": 0, "character": 46 }
+        },
+        "newText": "http://localhost:4545/x/a@v2.0.0"
+      }
+    }))
   );
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_workspace_symbol() {
-  let mut client = init("initialize_params.json");
+  let mut client = LspClientBuilder::new().build();
+  client.initialize_default();
   did_open(
     &mut client,
     json!({
@@ -6237,80 +7351,54 @@ fn lsp_workspace_symbol() {
         "location": {
           "uri": "file:///a/file.ts",
           "range": {
-            "start": {
-              "line": 1,
-              "character": 2
-            },
-            "end": {
-              "line": 1,
-              "character": 17
-            }
+            "start": { "line": 1, "character": 2 },
+            "end": { "line": 1, "character": 17 }
           }
         },
         "containerName": "A"
-      },
-      {
+      }, {
         "name": "fieldB",
         "kind": 8,
         "location": {
           "uri": "file:///a/file.ts",
           "range": {
-            "start": {
-              "line": 2,
-              "character": 2
-            },
-            "end": {
-              "line": 2,
-              "character": 17
-            }
+            "start": { "line": 2, "character": 2 },
+            "end": { "line": 2, "character": 17 }
           }
         },
         "containerName": "A"
-      },
-      {
+      }, {
         "name": "fieldC",
         "kind": 8,
         "location": {
           "uri": "file:///a/file_01.ts",
           "range": {
-            "start": {
-              "line": 1,
-              "character": 2
-            },
-            "end": {
-              "line": 1,
-              "character": 17
-            }
+            "start": { "line": 1, "character": 2 },
+            "end": { "line": 1, "character": 17 }
           }
         },
         "containerName": "B"
-      },
-      {
+      }, {
         "name": "fieldD",
         "kind": 8,
         "location": {
           "uri": "file:///a/file_01.ts",
           "range": {
-            "start": {
-              "line": 2,
-              "character": 2
-            },
-            "end": {
-              "line": 2,
-              "character": 17
-            }
+            "start": { "line": 2, "character": 2 },
+            "end": { "line": 2, "character": 17 }
           }
         },
         "containerName": "B"
       }
     ]))
   );
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_code_actions_ignore_lint() {
-  let mut client = init("initialize_params.json");
+  let mut client = LspClientBuilder::new().build();
+  client.initialize_default();
   did_open(
     &mut client,
     json!({
@@ -6325,21 +7413,121 @@ fn lsp_code_actions_ignore_lint() {
   let (maybe_res, maybe_err) = client
     .write_request(
       "textDocument/codeAction",
-      load_fixture("code_action_ignore_lint_params.json"),
+      json!({
+        "textDocument": {
+          "uri": "file:///a/file.ts"
+        },
+        "range": {
+          "start": { "line": 1, "character": 5 },
+          "end": { "line": 1, "character": 12 }
+        },
+        "context": {
+          "diagnostics": [
+            {
+              "range": {
+                "start": { "line": 1, "character": 5 },
+                "end": { "line": 1, "character": 12 }
+              },
+              "severity": 1,
+              "code": "prefer-const",
+              "source": "deno-lint",
+              "message": "'message' is never reassigned\nUse 'const' instead",
+              "relatedInformation": []
+            }
+          ],
+          "only": ["quickfix"]
+        }
+      }),
     )
     .unwrap();
   assert!(maybe_err.is_none());
   assert_eq!(
     maybe_res,
-    Some(load_fixture("code_action_ignore_lint_response.json"))
+    Some(json!([{
+      "title": "Disable prefer-const for this line",
+      "kind": "quickfix",
+      "diagnostics": [{
+        "range": {
+          "start": { "line": 1, "character": 5 },
+          "end": { "line": 1, "character": 12 }
+        },
+        "severity": 1,
+        "code": "prefer-const",
+        "source": "deno-lint",
+        "message": "'message' is never reassigned\nUse 'const' instead",
+        "relatedInformation": []
+      }],
+      "edit": {
+        "changes": {
+          "file:///a/file.ts": [{
+            "range": {
+              "start": { "line": 1, "character": 0 },
+              "end": { "line": 1, "character": 0 }
+            },
+            "newText": "// deno-lint-ignore prefer-const\n"
+          }]
+        }
+      }
+    }, {
+      "title": "Disable prefer-const for the entire file",
+      "kind": "quickfix",
+      "diagnostics": [{
+        "range": {
+          "start": { "line": 1, "character": 5 },
+          "end": { "line": 1, "character": 12 }
+        },
+        "severity": 1,
+        "code": "prefer-const",
+        "source": "deno-lint",
+        "message": "'message' is never reassigned\nUse 'const' instead",
+        "relatedInformation": []
+      }],
+      "edit": {
+        "changes": {
+          "file:///a/file.ts": [{
+            "range": {
+              "start": { "line": 0, "character": 0 },
+              "end": { "line": 0, "character": 0 }
+            },
+            "newText": "// deno-lint-ignore-file prefer-const\n"
+          }]
+        }
+      }
+    }, {
+      "title": "Ignore lint errors for the entire file",
+      "kind": "quickfix",
+      "diagnostics": [{
+        "range": {
+          "start": { "line": 1, "character": 5 },
+          "end": { "line": 1, "character": 12 }
+        },
+        "severity": 1,
+        "code": "prefer-const",
+        "source": "deno-lint",
+        "message": "'message' is never reassigned\nUse 'const' instead",
+        "relatedInformation": []
+      }],
+      "edit": {
+        "changes": {
+          "file:///a/file.ts": [{
+            "range": {
+              "start": { "line": 0, "character": 0 },
+              "end": { "line": 0, "character": 0 }
+            },
+            "newText": "// deno-lint-ignore-file\n"
+          }]
+        }
+      }
+    }]))
   );
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 /// This test exercises updating an existing deno-lint-ignore-file comment.
 #[test]
 fn lsp_code_actions_update_ignore_lint() {
-  let mut client = init("initialize_params.json");
+  let mut client = LspClientBuilder::new().build();
+  client.initialize_default();
   did_open(
     &mut client,
     json!({
@@ -6359,40 +7547,148 @@ console.log(snake_case);
   let (maybe_res, maybe_err) = client
     .write_request(
       "textDocument/codeAction",
-      load_fixture("code_action_update_ignore_lint_params.json"),
+      json!({
+        "textDocument": {
+          "uri": "file:///a/file.ts"
+        },
+        "range": {
+          "start": { "line": 3, "character": 5 },
+          "end": { "line": 3, "character": 15 }
+        },
+        "context": {
+          "diagnostics": [{
+            "range": {
+              "start": { "line": 3, "character": 5 },
+              "end": { "line": 3, "character": 15 }
+            },
+            "severity": 1,
+            "code": "prefer-const",
+            "source": "deno-lint",
+            "message": "'snake_case' is never reassigned\nUse 'const' instead",
+            "relatedInformation": []
+          }],
+          "only": ["quickfix"]
+        }
+      }),
     )
     .unwrap();
   assert!(maybe_err.is_none());
   assert_eq!(
     maybe_res,
-    Some(load_fixture("code_action_update_ignore_lint_response.json"))
+    Some(json!([{
+      "title": "Disable prefer-const for this line",
+      "kind": "quickfix",
+      "diagnostics": [{
+        "range": {
+          "start": { "line": 3, "character": 5 },
+          "end": { "line": 3, "character": 15 }
+        },
+        "severity": 1,
+        "code": "prefer-const",
+        "source": "deno-lint",
+        "message": "'snake_case' is never reassigned\nUse 'const' instead",
+        "relatedInformation": []
+      }],
+      "edit": {
+        "changes": {
+          "file:///a/file.ts": [{
+            "range": {
+              "start": { "line": 3, "character": 0 },
+              "end": { "line": 3, "character": 0 }
+            },
+            "newText": "// deno-lint-ignore prefer-const\n"
+          }]
+        }
+      }
+    }, {
+      "title": "Disable prefer-const for the entire file",
+      "kind": "quickfix",
+      "diagnostics": [{
+        "range": {
+          "start": { "line": 3, "character": 5 },
+          "end": { "line": 3, "character": 15 }
+        },
+        "severity": 1,
+        "code": "prefer-const",
+        "source": "deno-lint",
+        "message": "'snake_case' is never reassigned\nUse 'const' instead",
+        "relatedInformation": []
+      }],
+      "edit": {
+        "changes": {
+          "file:///a/file.ts": [{
+            "range": {
+              "start": { "line": 1, "character": 34 },
+              "end": { "line": 1, "character": 34 }
+            },
+            "newText": " prefer-const"
+          }]
+        }
+      }
+    }, {
+      "title": "Ignore lint errors for the entire file",
+      "kind": "quickfix",
+      "diagnostics": [{
+        "range": {
+          "start": { "line": 3, "character": 5 },
+          "end": { "line": 3, "character": 15 }
+        },
+        "severity": 1,
+        "code": "prefer-const",
+        "source": "deno-lint",
+        "message": "'snake_case' is never reassigned\nUse 'const' instead",
+        "relatedInformation": []
+      }],
+      "edit": {
+        "changes": {
+          "file:///a/file.ts": [{
+            "range": {
+              "start": { "line": 0, "character": 0 },
+              "end": { "line": 0, "character": 0 }
+            },
+            "newText": "// deno-lint-ignore-file\n"
+          }]
+        }
+      }
+    }]))
   );
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_lint_with_config() {
-  let temp_dir = TempDir::new();
-  let mut params: lsp::InitializeParams =
-    serde_json::from_value(load_fixture("initialize_params.json")).unwrap();
-  let deno_lint_jsonc =
-    serde_json::to_vec_pretty(&load_fixture("deno.lint.jsonc")).unwrap();
-  fs::write(temp_dir.path().join("deno.lint.jsonc"), deno_lint_jsonc).unwrap();
-
-  params.root_uri = Some(Url::from_file_path(temp_dir.path()).unwrap());
-  if let Some(Value::Object(mut map)) = params.initialization_options {
-    map.insert("config".to_string(), json!("./deno.lint.jsonc"));
-    params.initialization_options = Some(Value::Object(map));
+  let context = TestContextBuilder::new().build();
+  let temp_dir = context.deno_dir();
+
+  temp_dir.write(
+    "deno.lint.jsonc",
+    r#"{
+    "lint": {
+      "rules": {
+        "exclude": ["camelcase"],
+        "include": ["ban-untagged-todo"],
+        "tags": []
+      }
+    }
   }
+  "#,
+  );
+
+  let mut client = context.new_lsp_command().build();
+  client.initialize(|builder| {
+    builder.set_config("./deno.lint.jsonc");
+  });
 
-  let deno_exe = deno_exe_path();
-  let mut client = LspClient::new(&deno_exe, false).unwrap();
-  client
-    .write_request::<_, _, Value>("initialize", params)
-    .unwrap();
   let mut session = TestSession::from_client(client);
 
-  let diagnostics = session.did_open(load_fixture("did_open_lint.json"));
+  let diagnostics = session.did_open(json!({
+    "textDocument": {
+      "uri": "file:///a/file.ts",
+      "languageId": "typescript",
+      "version": 1,
+      "text": "// TODO: fixme\nexport async function non_camel_case() {\nconsole.log(\"finished!\")\n}"
+    }
+  }));
   let diagnostics = diagnostics.viewed();
   assert_eq!(diagnostics.len(), 1);
   assert_eq!(
@@ -6404,25 +7700,29 @@ fn lsp_lint_with_config() {
 
 #[test]
 fn lsp_lint_exclude_with_config() {
-  let temp_dir = TempDir::new();
-  let mut params: lsp::InitializeParams =
-    serde_json::from_value(load_fixture("initialize_params.json")).unwrap();
-  let deno_lint_jsonc =
-    serde_json::to_vec_pretty(&load_fixture("deno.lint.exclude.jsonc"))
-      .unwrap();
-  fs::write(temp_dir.path().join("deno.lint.jsonc"), deno_lint_jsonc).unwrap();
+  let context = TestContextBuilder::new().build();
+  let temp_dir = context.deno_dir();
 
-  params.root_uri = Some(Url::from_file_path(temp_dir.path()).unwrap());
-  if let Some(Value::Object(mut map)) = params.initialization_options {
-    map.insert("config".to_string(), json!("./deno.lint.jsonc"));
-    params.initialization_options = Some(Value::Object(map));
-  }
+  temp_dir.write(
+    "deno.lint.jsonc",
+    r#"{
+      "lint": {
+        "files": {
+          "exclude": ["ignored.ts"]
+        },
+        "rules": {
+          "exclude": ["camelcase"],
+          "include": ["ban-untagged-todo"],
+          "tags": []
+        }
+      }
+    }"#,
+  );
 
-  let deno_exe = deno_exe_path();
-  let mut client = LspClient::new(&deno_exe, false).unwrap();
-  client
-    .write_request::<_, _, Value>("initialize", params)
-    .unwrap();
+  let mut client = context.new_lsp_command().build();
+  client.initialize(|builder| {
+    builder.set_config("./deno.lint.jsonc");
+  });
 
   let diagnostics = did_open(
     &mut client,
@@ -6440,13 +7740,14 @@ fn lsp_lint_exclude_with_config() {
     .flat_map(|x| x.diagnostics)
     .collect::<Vec<_>>();
   assert_eq!(diagnostics, Vec::new());
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[test]
 fn lsp_jsx_import_source_pragma() {
-  let _g = http_server();
-  let mut client = init("initialize_params.json");
+  let context = TestContextBuilder::new().use_http_server().build();
+  let mut client = context.new_lsp_command().build();
+  client.initialize_default();
   did_open(
     &mut client,
     json!({
@@ -6475,11 +7776,9 @@ export function B() {
         "referrer": {
           "uri": "file:///a/file.tsx",
         },
-        "uris": [
-          {
-            "uri": "http://127.0.0.1:4545/jsx/jsx-runtime",
-          }
-        ],
+        "uris": [{
+          "uri": "http://127.0.0.1:4545/jsx/jsx-runtime",
+        }],
       }),
     )
     .unwrap();
@@ -6492,10 +7791,7 @@ export function B() {
         "textDocument": {
           "uri": "file:///a/file.tsx"
         },
-        "position": {
-          "line": 0,
-          "character": 25
-        }
+        "position": { "line": 0, "character": 25 }
       }),
     )
     .unwrap();
@@ -6508,18 +7804,12 @@ export function B() {
         "value": "**Resolved Dependency**\n\n**Code**: http&#8203;://localhost:4545/jsx/jsx-runtime\n",
       },
       "range": {
-        "start": {
-          "line": 0,
-          "character": 21
-        },
-        "end": {
-          "line": 0,
-          "character": 46
-        }
+        "start": { "line": 0, "character": 21 },
+        "end": { "line": 0, "character": 46 }
       }
     }))
   );
-  shutdown(&mut client);
+  client.shutdown();
 }
 
 #[derive(Debug, Clone, Deserialize, PartialEq)]
@@ -6562,15 +7852,9 @@ struct TestRunResponseParams {
 
 #[test]
 fn lsp_testing_api() {
-  let mut params: lsp::InitializeParams =
-    serde_json::from_value(load_fixture("initialize_params.json")).unwrap();
-  let temp_dir = TempDir::new();
-
-  let root_specifier =
-    ensure_directory_specifier(Url::from_file_path(temp_dir.path()).unwrap());
+  let context = TestContextBuilder::new().build();
+  let temp_dir = context.deno_dir();
 
-  let module_path = temp_dir.path().join("./test.ts");
-  let specifier = ModuleSpecifier::from_file_path(&module_path).unwrap();
   let contents = r#"
 Deno.test({
   name: "test a",
@@ -6579,18 +7863,12 @@ Deno.test({
   }
 });
 "#;
-  fs::write(&module_path, contents).unwrap();
-  fs::write(temp_dir.path().join("./deno.jsonc"), r#"{}"#).unwrap();
-
-  params.root_uri = Some(root_specifier);
-
-  let deno_exe = deno_exe_path();
-  let mut client = LspClient::new(&deno_exe, false).unwrap();
-  client
-    .write_request::<_, _, Value>("initialize", params)
-    .unwrap();
+  temp_dir.write("./test.ts", contents);
+  temp_dir.write("./deno.jsonc", "{}");
+  let specifier = temp_dir.uri().join("test.ts").unwrap();
 
-  client.write_notification("initialized", json!({})).unwrap();
+  let mut client = context.new_lsp_command().build();
+  client.initialize_default();
 
   client
     .write_notification(
@@ -6763,5 +8041,5 @@ Deno.test({
     _ => panic!("unexpected message {}", json!(notification)),
   }
 
-  shutdown(&mut client);
+  client.shutdown();
 }
diff --git a/cli/tests/testdata/lsp/a.d.ts b/cli/tests/testdata/lsp/a.d.ts
deleted file mode 100644
index 536a6d0a69c963..00000000000000
--- a/cli/tests/testdata/lsp/a.d.ts
+++ /dev/null
@@ -1,2 +0,0 @@
-// deno-lint-ignore-file no-var
-declare var a: string;
diff --git a/cli/tests/testdata/lsp/b.d.ts b/cli/tests/testdata/lsp/b.d.ts
deleted file mode 100644
index 2fd56623b591ff..00000000000000
--- a/cli/tests/testdata/lsp/b.d.ts
+++ /dev/null
@@ -1,2 +0,0 @@
-// deno-lint-ignore-file no-var
-declare var b: string;
diff --git a/cli/tests/testdata/lsp/code_action_ignore_lint_params.json b/cli/tests/testdata/lsp/code_action_ignore_lint_params.json
deleted file mode 100644
index 7711812fdb10ee..00000000000000
--- a/cli/tests/testdata/lsp/code_action_ignore_lint_params.json
+++ /dev/null
@@ -1,39 +0,0 @@
-{
-  "textDocument": {
-    "uri": "file:///a/file.ts"
-  },
-  "range": {
-    "start": {
-      "line": 1,
-      "character": 5
-    },
-    "end": {
-      "line": 1,
-      "character": 12
-    }
-  },
-  "context": {
-    "diagnostics": [
-      {
-        "range": {
-          "start": {
-            "line": 1,
-            "character": 5
-          },
-          "end": {
-            "line": 1,
-            "character": 12
-          }
-        },
-        "severity": 1,
-        "code": "prefer-const",
-        "source": "deno-lint",
-        "message": "'message' is never reassigned\nUse 'const' instead",
-        "relatedInformation": []
-      }
-    ],
-    "only": [
-      "quickfix"
-    ]
-  }
-}
diff --git a/cli/tests/testdata/lsp/code_action_ignore_lint_response.json b/cli/tests/testdata/lsp/code_action_ignore_lint_response.json
deleted file mode 100644
index d15fccca96219d..00000000000000
--- a/cli/tests/testdata/lsp/code_action_ignore_lint_response.json
+++ /dev/null
@@ -1,92 +0,0 @@
-[
-  {
-    "title": "Disable prefer-const for this line",
-    "kind": "quickfix",
-    "diagnostics": [
-      {
-        "range": {
-          "start": { "line": 1, "character": 5 },
-          "end": { "line": 1, "character": 12 }
-        },
-        "severity": 1,
-        "code": "prefer-const",
-        "source": "deno-lint",
-        "message": "'message' is never reassigned\nUse 'const' instead",
-        "relatedInformation": []
-      }
-    ],
-    "edit": {
-      "changes": {
-        "file:///a/file.ts": [
-          {
-            "range": {
-              "start": { "line": 1, "character": 0 },
-              "end": { "line": 1, "character": 0 }
-            },
-            "newText": "// deno-lint-ignore prefer-const\n"
-          }
-        ]
-      }
-    }
-  },
-  {
-    "title": "Disable prefer-const for the entire file",
-    "kind": "quickfix",
-    "diagnostics": [
-      {
-        "range": {
-          "start": { "line": 1, "character": 5 },
-          "end": { "line": 1, "character": 12 }
-        },
-        "severity": 1,
-        "code": "prefer-const",
-        "source": "deno-lint",
-        "message": "'message' is never reassigned\nUse 'const' instead",
-        "relatedInformation": []
-      }
-    ],
-    "edit": {
-      "changes": {
-        "file:///a/file.ts": [
-          {
-            "range": {
-              "start": { "line": 0, "character": 0 },
-              "end": { "line": 0, "character": 0 }
-            },
-            "newText": "// deno-lint-ignore-file prefer-const\n"
-          }
-        ]
-      }
-    }
-  },
-  {
-    "title": "Ignore lint errors for the entire file",
-    "kind": "quickfix",
-    "diagnostics": [
-      {
-        "range": {
-          "start": { "line": 1, "character": 5 },
-          "end": { "line": 1, "character": 12 }
-        },
-        "severity": 1,
-        "code": "prefer-const",
-        "source": "deno-lint",
-        "message": "'message' is never reassigned\nUse 'const' instead",
-        "relatedInformation": []
-      }
-    ],
-    "edit": {
-      "changes": {
-        "file:///a/file.ts": [
-          {
-            "range": {
-              "start": { "line": 0, "character": 0 },
-              "end": { "line": 0, "character": 0 }
-            },
-            "newText": "// deno-lint-ignore-file\n"
-          }
-        ]
-      }
-    }
-  }
-]
diff --git a/cli/tests/testdata/lsp/code_action_params.json b/cli/tests/testdata/lsp/code_action_params.json
deleted file mode 100644
index d026d61f6873de..00000000000000
--- a/cli/tests/testdata/lsp/code_action_params.json
+++ /dev/null
@@ -1,39 +0,0 @@
-{
-  "textDocument": {
-    "uri": "file:///a/file.ts"
-  },
-  "range": {
-    "start": {
-      "line": 1,
-      "character": 2
-    },
-    "end": {
-      "line": 1,
-      "character": 7
-    }
-  },
-  "context": {
-    "diagnostics": [
-      {
-        "range": {
-          "start": {
-            "line": 1,
-            "character": 2
-          },
-          "end": {
-            "line": 1,
-            "character": 7
-          }
-        },
-        "severity": 1,
-        "code": 1308,
-        "source": "deno-ts",
-        "message": "'await' expressions are only allowed within async functions and at the top levels of modules.",
-        "relatedInformation": []
-      }
-    ],
-    "only": [
-      "quickfix"
-    ]
-  }
-}
diff --git a/cli/tests/testdata/lsp/code_action_params_cache.json b/cli/tests/testdata/lsp/code_action_params_cache.json
deleted file mode 100644
index 61ae555a3ce19d..00000000000000
--- a/cli/tests/testdata/lsp/code_action_params_cache.json
+++ /dev/null
@@ -1,41 +0,0 @@
-{
-  "textDocument": {
-    "uri": "file:///a/file.ts"
-  },
-  "range": {
-    "start": {
-      "line": 0,
-      "character": 19
-    },
-    "end": {
-      "line": 0,
-      "character": 49
-    }
-  },
-  "context": {
-    "diagnostics": [
-      {
-        "range": {
-          "start": {
-            "line": 0,
-            "character": 19
-          },
-          "end": {
-            "line": 0,
-            "character": 49
-          }
-        },
-        "severity": 1,
-        "code": "no-cache",
-        "source": "deno",
-        "message": "Unable to load the remote module: \"https://deno.land/x/a/mod.ts\".",
-        "data": {
-          "specifier": "https://deno.land/x/a/mod.ts"
-        }
-      }
-    ],
-    "only": [
-      "quickfix"
-    ]
-  }
-}
diff --git a/cli/tests/testdata/lsp/code_action_params_deadlock.json b/cli/tests/testdata/lsp/code_action_params_deadlock.json
deleted file mode 100644
index be0e317e1dfe14..00000000000000
--- a/cli/tests/testdata/lsp/code_action_params_deadlock.json
+++ /dev/null
@@ -1,38 +0,0 @@
-{
-  "textDocument": {
-    "uri": "file:///a/file.ts"
-  },
-  "range": {
-    "start": {
-      "line": 441,
-      "character": 33
-    },
-    "end": {
-      "line": 441,
-      "character": 42
-    }
-  },
-  "context": {
-    "diagnostics": [
-      {
-        "range": {
-          "start": {
-            "line": 441,
-            "character": 33
-          },
-          "end": {
-            "line": 441,
-            "character": 42
-          }
-        },
-        "severity": 1,
-        "code": 7031,
-        "source": "deno-ts",
-        "message": "Binding element 'debugFlag' implicitly has an 'any' type."
-      }
-    ],
-    "only": [
-      "quickfix"
-    ]
-  }
-}
diff --git a/cli/tests/testdata/lsp/code_action_params_import_assertion.json b/cli/tests/testdata/lsp/code_action_params_import_assertion.json
deleted file mode 100644
index 67b822a424400e..00000000000000
--- a/cli/tests/testdata/lsp/code_action_params_import_assertion.json
+++ /dev/null
@@ -1,38 +0,0 @@
-{
-  "textDocument": {
-    "uri": "file:///a/a.ts"
-  },
-  "range": {
-    "start": {
-      "line": 0,
-      "character": 14
-    },
-    "end": {
-      "line": 0,
-      "character": 27
-    }
-  },
-  "context": {
-    "diagnostics": [
-      {
-        "range": {
-          "start": {
-            "line": 0,
-            "character": 14
-          },
-          "end": {
-            "line": 0,
-            "character": 27
-          }
-        },
-        "severity": 1,
-        "code": "no-assert-type",
-        "source": "deno",
-        "message": "The module is a JSON module and not being imported with an import assertion. Consider adding `assert { type: \"json\" }` to the import statement."
-      }
-    ],
-    "only": [
-      "quickfix"
-    ]
-  }
-}
diff --git a/cli/tests/testdata/lsp/code_action_params_imports.json b/cli/tests/testdata/lsp/code_action_params_imports.json
deleted file mode 100644
index 891257ca01bfe8..00000000000000
--- a/cli/tests/testdata/lsp/code_action_params_imports.json
+++ /dev/null
@@ -1,54 +0,0 @@
-{
-  "textDocument": {
-    "uri": "file:///a/file00.ts"
-  },
-  "range": {
-    "start": {
-      "line": 0,
-      "character": 0
-    },
-    "end": {
-      "line": 6,
-      "character": 0
-    }
-  },
-  "context": {
-    "diagnostics": [
-      {
-        "range": {
-          "start": {
-            "line": 0,
-            "character": 50
-          },
-          "end": {
-            "line": 0,
-            "character": 67
-          }
-        },
-        "severity": 1,
-        "code": 2304,
-        "source": "deno-ts",
-        "message": "Cannot find name 'DuckConfigOptions'."
-      },
-      {
-        "range": {
-          "start": {
-            "line": 4,
-            "character": 39
-          },
-          "end": {
-            "line": 4,
-            "character": 49
-          }
-        },
-        "severity": 1,
-        "code": 2304,
-        "source": "deno-ts",
-        "message": "Cannot find name 'DuckConfig'."
-      }
-    ],
-    "only": [
-      "quickfix"
-    ]
-  }
-}
diff --git a/cli/tests/testdata/lsp/code_action_params_refactor.json b/cli/tests/testdata/lsp/code_action_params_refactor.json
deleted file mode 100644
index 121c400ed90e67..00000000000000
--- a/cli/tests/testdata/lsp/code_action_params_refactor.json
+++ /dev/null
@@ -1,21 +0,0 @@
-{
-  "textDocument": {
-    "uri": "file:///a/file.ts"
-  },
-  "range": {
-    "start": {
-      "line": 0,
-      "character": 0
-    },
-    "end": {
-      "line": 1,
-      "character": 0
-    }
-  },
-  "context": {
-    "diagnostics": [],
-    "only": [
-      "refactor"
-    ]
-  }
-}
diff --git a/cli/tests/testdata/lsp/code_action_redirect_response.json b/cli/tests/testdata/lsp/code_action_redirect_response.json
deleted file mode 100644
index 2351275703989d..00000000000000
--- a/cli/tests/testdata/lsp/code_action_redirect_response.json
+++ /dev/null
@@ -1,47 +0,0 @@
-[
-  {
-    "title": "Update specifier to its redirected specifier.",
-    "kind": "quickfix",
-    "diagnostics": [
-      {
-        "range": {
-          "start": {
-            "line": 0,
-            "character": 19
-          },
-          "end": {
-            "line": 0,
-            "character": 60
-          }
-        },
-        "severity": 3,
-        "code": "redirect",
-        "source": "deno",
-        "message": "The import of \"http://127.0.0.1:4545/x_deno_warning.js\" was redirected to \"http://127.0.0.1:4545/lsp/x_deno_warning_redirect.js\".",
-        "data": {
-          "specifier": "http://127.0.0.1:4545/x_deno_warning.js",
-          "redirect": "http://127.0.0.1:4545/lsp/x_deno_warning_redirect.js"
-        }
-      }
-    ],
-    "edit": {
-      "changes": {
-        "file:///a/file.ts": [
-          {
-            "range": {
-              "start": {
-                "line": 0,
-                "character": 19
-              },
-              "end": {
-                "line": 0,
-                "character": 60
-              }
-            },
-            "newText": "\"http://127.0.0.1:4545/lsp/x_deno_warning_redirect.js\""
-          }
-        ]
-      }
-    }
-  }
-]
diff --git a/cli/tests/testdata/lsp/code_action_resolve_params.json b/cli/tests/testdata/lsp/code_action_resolve_params.json
deleted file mode 100644
index 50c1f9a43b7f70..00000000000000
--- a/cli/tests/testdata/lsp/code_action_resolve_params.json
+++ /dev/null
@@ -1,27 +0,0 @@
-{
-  "title": "Add all missing 'async' modifiers",
-  "kind": "quickfix",
-  "diagnostics": [
-    {
-      "range": {
-        "start": {
-          "line": 1,
-          "character": 2
-        },
-        "end": {
-          "line": 1,
-          "character": 7
-        }
-      },
-      "severity": 1,
-      "code": 1308,
-      "source": "deno-ts",
-      "message": "'await' expressions are only allowed within async functions and at the top levels of modules.",
-      "relatedInformation": []
-    }
-  ],
-  "data": {
-    "specifier": "file:///a/file.ts",
-    "fixId": "fixAwaitInSyncFunction"
-  }
-}
diff --git a/cli/tests/testdata/lsp/code_action_resolve_params_imports.json b/cli/tests/testdata/lsp/code_action_resolve_params_imports.json
deleted file mode 100644
index 5e1beb87bc0774..00000000000000
--- a/cli/tests/testdata/lsp/code_action_resolve_params_imports.json
+++ /dev/null
@@ -1,42 +0,0 @@
-{
-  "title": "Add all missing imports",
-  "kind": "quickfix",
-  "diagnostics": [
-    {
-      "range": {
-        "start": {
-          "line": 0,
-          "character": 50
-        },
-        "end": {
-          "line": 0,
-          "character": 67
-        }
-      },
-      "severity": 1,
-      "code": 2304,
-      "source": "deno-ts",
-      "message": "Cannot find name 'DuckConfigOptions'."
-    },
-    {
-      "range": {
-        "start": {
-          "line": 4,
-          "character": 39
-        },
-        "end": {
-          "line": 4,
-          "character": 49
-        }
-      },
-      "severity": 1,
-      "code": 2304,
-      "source": "deno-ts",
-      "message": "Cannot find name 'DuckConfig'."
-    }
-  ],
-  "data": {
-    "specifier": "file:///a/file00.ts",
-    "fixId": "fixMissingImport"
-  }
-}
diff --git a/cli/tests/testdata/lsp/code_action_resolve_params_refactor.json b/cli/tests/testdata/lsp/code_action_resolve_params_refactor.json
deleted file mode 100644
index d4bb3bd81c5c7b..00000000000000
--- a/cli/tests/testdata/lsp/code_action_resolve_params_refactor.json
+++ /dev/null
@@ -1,20 +0,0 @@
-{
-  "title": "Extract to interface",
-  "kind": "refactor.extract.interface",
-  "isPreferred": true,
-  "data": {
-    "specifier": "file:///a/file.ts",
-    "range": {
-      "start": {
-        "line": 0,
-        "character": 7
-      },
-      "end": {
-        "line": 0,
-        "character": 33
-      }
-    },
-    "refactorName": "Extract type",
-    "actionName": "Extract to interface"
-  }
-}
diff --git a/cli/tests/testdata/lsp/code_action_resolve_response.json b/cli/tests/testdata/lsp/code_action_resolve_response.json
deleted file mode 100644
index e3f5b3f0edf185..00000000000000
--- a/cli/tests/testdata/lsp/code_action_resolve_response.json
+++ /dev/null
@@ -1,91 +0,0 @@
-{
-  "title": "Add all missing 'async' modifiers",
-  "kind": "quickfix",
-  "diagnostics": [
-    {
-      "range": {
-        "start": {
-          "line": 1,
-          "character": 2
-        },
-        "end": {
-          "line": 1,
-          "character": 7
-        }
-      },
-      "severity": 1,
-      "code": 1308,
-      "source": "deno-ts",
-      "message": "'await' expressions are only allowed within async functions and at the top levels of modules.",
-      "relatedInformation": []
-    }
-  ],
-  "edit": {
-    "documentChanges": [
-      {
-        "textDocument": {
-          "uri": "file:///a/file.ts",
-          "version": 1
-        },
-        "edits": [
-          {
-            "range": {
-              "start": {
-                "line": 0,
-                "character": 7
-              },
-              "end": {
-                "line": 0,
-                "character": 7
-              }
-            },
-            "newText": "async "
-          },
-          {
-            "range": {
-              "start": {
-                "line": 0,
-                "character": 21
-              },
-              "end": {
-                "line": 0,
-                "character": 25
-              }
-            },
-            "newText": "Promise<void>"
-          },
-          {
-            "range": {
-              "start": {
-                "line": 4,
-                "character": 7
-              },
-              "end": {
-                "line": 4,
-                "character": 7
-              }
-            },
-            "newText": "async "
-          },
-          {
-            "range": {
-              "start": {
-                "line": 4,
-                "character": 21
-              },
-              "end": {
-                "line": 4,
-                "character": 25
-              }
-            },
-            "newText": "Promise<void>"
-          }
-        ]
-      }
-    ]
-  },
-  "data": {
-    "specifier": "file:///a/file.ts",
-    "fixId": "fixAwaitInSyncFunction"
-  }
-}
diff --git a/cli/tests/testdata/lsp/code_action_resolve_response_imports.json b/cli/tests/testdata/lsp/code_action_resolve_response_imports.json
deleted file mode 100644
index 6ffc3192ed3ae3..00000000000000
--- a/cli/tests/testdata/lsp/code_action_resolve_response_imports.json
+++ /dev/null
@@ -1,67 +0,0 @@
-{
-  "title": "Add all missing imports",
-  "kind": "quickfix",
-  "diagnostics": [
-    {
-      "range": {
-        "start": {
-          "line": 0,
-          "character": 50
-        },
-        "end": {
-          "line": 0,
-          "character": 67
-        }
-      },
-      "severity": 1,
-      "code": 2304,
-      "source": "deno-ts",
-      "message": "Cannot find name 'DuckConfigOptions'."
-    },
-    {
-      "range": {
-        "start": {
-          "line": 4,
-          "character": 39
-        },
-        "end": {
-          "line": 4,
-          "character": 49
-        }
-      },
-      "severity": 1,
-      "code": 2304,
-      "source": "deno-ts",
-      "message": "Cannot find name 'DuckConfig'."
-    }
-  ],
-  "edit": {
-    "documentChanges": [
-      {
-        "textDocument": {
-          "uri": "file:///a/file00.ts",
-          "version": 1
-        },
-        "edits": [
-          {
-            "range": {
-              "start": {
-                "line": 0,
-                "character": 0
-              },
-              "end": {
-                "line": 0,
-                "character": 0
-              }
-            },
-            "newText": "import { DuckConfig } from \"./file01.ts\";\nimport { DuckConfigOptions } from \"./file02.ts\";\n\n"
-          }
-        ]
-      }
-    ]
-  },
-  "data": {
-    "specifier": "file:///a/file00.ts",
-    "fixId": "fixMissingImport"
-  }
-}
diff --git a/cli/tests/testdata/lsp/code_action_resolve_response_refactor.json b/cli/tests/testdata/lsp/code_action_resolve_response_refactor.json
deleted file mode 100644
index 721a76a6b82b11..00000000000000
--- a/cli/tests/testdata/lsp/code_action_resolve_response_refactor.json
+++ /dev/null
@@ -1,58 +0,0 @@
-{
-  "title": "Extract to interface",
-  "kind": "refactor.extract.interface",
-  "edit": {
-    "documentChanges": [
-      {
-        "textDocument": {
-          "uri": "file:///a/file.ts",
-          "version": 1
-        },
-        "edits": [
-          {
-            "range": {
-              "start": {
-                "line": 0,
-                "character": 0
-              },
-              "end": {
-                "line": 0,
-                "character": 0
-              }
-            },
-            "newText": "interface NewType {\n  a?: number;\n  b?: string;\n}\n\n"
-          },
-          {
-            "range": {
-              "start": {
-                "line": 0,
-                "character": 7
-              },
-              "end": {
-                "line": 0,
-                "character": 33
-              }
-            },
-            "newText": "NewType"
-          }
-        ]
-      }
-    ]
-  },
-  "isPreferred": true,
-  "data": {
-    "specifier": "file:///a/file.ts",
-    "range": {
-      "start": {
-        "line": 0,
-        "character": 7
-      },
-      "end": {
-        "line": 0,
-        "character": 33
-      }
-    },
-    "refactorName": "Extract type",
-    "actionName": "Extract to interface"
-  }
-}
diff --git a/cli/tests/testdata/lsp/code_action_response.json b/cli/tests/testdata/lsp/code_action_response.json
deleted file mode 100644
index ab30898f8ec0a4..00000000000000
--- a/cli/tests/testdata/lsp/code_action_response.json
+++ /dev/null
@@ -1,90 +0,0 @@
-[
-  {
-    "title": "Add async modifier to containing function",
-    "kind": "quickfix",
-    "diagnostics": [
-      {
-        "range": {
-          "start": {
-            "line": 1,
-            "character": 2
-          },
-          "end": {
-            "line": 1,
-            "character": 7
-          }
-        },
-        "severity": 1,
-        "code": 1308,
-        "source": "deno-ts",
-        "message": "'await' expressions are only allowed within async functions and at the top levels of modules.",
-        "relatedInformation": []
-      }
-    ],
-    "edit": {
-      "documentChanges": [
-        {
-          "textDocument": {
-            "uri": "file:///a/file.ts",
-            "version": 1
-          },
-          "edits": [
-            {
-              "range": {
-                "start": {
-                  "line": 0,
-                  "character": 7
-                },
-                "end": {
-                  "line": 0,
-                  "character": 7
-                }
-              },
-              "newText": "async "
-            },
-            {
-              "range": {
-                "start": {
-                  "line": 0,
-                  "character": 21
-                },
-                "end": {
-                  "line": 0,
-                  "character": 25
-                }
-              },
-              "newText": "Promise<void>"
-            }
-          ]
-        }
-      ]
-    }
-  },
-  {
-    "title": "Add all missing 'async' modifiers",
-    "kind": "quickfix",
-    "diagnostics": [
-      {
-        "range": {
-          "start": {
-            "line": 1,
-            "character": 2
-          },
-          "end": {
-            "line": 1,
-            "character": 7
-          }
-        },
-        "severity": 1,
-        "code": 1308,
-        "source": "deno-ts",
-        "message": "'await' expressions are only allowed within async functions and at the top levels of modules.",
-        "relatedInformation": []
-      }
-    ],
-    "data": {
-      "specifier": "file:///a/file.ts",
-      "fixId": "fixAwaitInSyncFunction"
-    }
-  }
-]
diff --git a/cli/tests/testdata/lsp/code_action_response_cache.json b/cli/tests/testdata/lsp/code_action_response_cache.json
deleted file mode 100644
index c56b350233e17c..00000000000000
--- a/cli/tests/testdata/lsp/code_action_response_cache.json
+++ /dev/null
@@ -1,36 +0,0 @@
-[
-  {
-    "title": "Cache \"https://deno.land/x/a/mod.ts\" and its dependencies.",
-    "kind": "quickfix",
-    "diagnostics": [
-      {
-        "range": {
-          "start": {
-            "line": 0,
-            "character": 19
-          },
-          "end": {
-            "line": 0,
-            "character": 49
-          }
-        },
-        "severity": 1,
-        "code": "no-cache",
-        "source": "deno",
-        "message": "Unable to load the remote module: \"https://deno.land/x/a/mod.ts\".",
-        "data": {
-          "specifier": "https://deno.land/x/a/mod.ts"
-        }
-      }
-    ],
-    "command": {
-      "title": "",
-      "command": "deno.cache",
-      "arguments": [
-        [
-          "https://deno.land/x/a/mod.ts"
-        ]
-      ]
-    }
-  }
-]
diff --git a/cli/tests/testdata/lsp/code_action_response_import_assertion.json b/cli/tests/testdata/lsp/code_action_response_import_assertion.json
deleted file mode 100644
index bff934b215d0a7..00000000000000
--- a/cli/tests/testdata/lsp/code_action_response_import_assertion.json
+++ /dev/null
@@ -1,43 +0,0 @@
-[
-  {
-    "title": "Insert import assertion.",
-    "kind": "quickfix",
-    "diagnostics": [
-      {
-        "range": {
-          "start": {
-            "line": 0,
-            "character": 14
-          },
-          "end": {
-            "line": 0,
-            "character": 27
-          }
-        },
-        "severity": 1,
-        "code": "no-assert-type",
-        "source": "deno",
-        "message": "The module is a JSON module and not being imported with an import assertion. Consider adding `assert { type: \"json\" }` to the import statement."
-      }
-    ],
-    "edit": {
-      "changes": {
-        "file:///a/a.ts": [
-          {
-            "range": {
-              "start": {
-                "line": 0,
-                "character": 27
-              },
-              "end": {
-                "line": 0,
-                "character": 27
-              }
-            },
-            "newText": " assert { type: \"json\" }"
-          }
-        ]
-      }
-    }
-  }
-]
diff --git a/cli/tests/testdata/lsp/code_action_response_imports.json b/cli/tests/testdata/lsp/code_action_response_imports.json
deleted file mode 100644
index 23eb6645d3e0a5..00000000000000
--- a/cli/tests/testdata/lsp/code_action_response_imports.json
+++ /dev/null
@@ -1,122 +0,0 @@
-[
-  {
-    "title": "Add import from \"./file02.ts\"",
-    "kind": "quickfix",
-    "diagnostics": [
-      {
-        "range": {
-          "start": {
-            "line": 0,
-            "character": 50
-          },
-          "end": {
-            "line": 0,
-            "character": 67
-          }
-        },
-        "severity": 1,
-        "code": 2304,
-        "source": "deno-ts",
-        "message": "Cannot find name 'DuckConfigOptions'."
-      }
-    ],
-    "edit": {
-      "documentChanges": [
-        {
-          "textDocument": {
-            "uri": "file:///a/file00.ts",
-            "version": 1
-          },
-          "edits": [
-            {
-              "range": {
-                "start": {
-                  "line": 0,
-                  "character": 0
-                },
-                "end": {
-                  "line": 0,
-                  "character": 0
-                }
-              },
-              "newText": "import { DuckConfigOptions } from \"./file02.ts\";\n\n"
-            }
-          ]
-        }
-      ]
-    }
-  },
-  {
-    "title": "Add all missing imports",
-    "kind": "quickfix",
-    "diagnostics": [
-      {
-        "range": {
-          "start": {
-            "line": 0,
-            "character": 50
-          },
-          "end": {
-            "line": 0,
-            "character": 67
-          }
-        },
-        "severity": 1,
-        "code": 2304,
-        "source": "deno-ts",
-        "message": "Cannot find name 'DuckConfigOptions'."
-      }
-    ],
-    "data": {
-      "specifier": "file:///a/file00.ts",
-      "fixId": "fixMissingImport"
-    }
-  },
-  {
-    "title": "Add import from \"./file01.ts\"",
-    "kind": "quickfix",
-    "diagnostics": [
-      {
-        "range": {
-          "start": {
-            "line": 4,
-            "character": 39
-          },
-          "end": {
-            "line": 4,
-            "character": 49
-          }
-        },
-        "severity": 1,
-        "code": 2304,
-        "source": "deno-ts",
-        "message": "Cannot find name 'DuckConfig'."
-      }
-    ],
-    "edit": {
-      "documentChanges": [
-        {
-          "textDocument": {
-            "uri": "file:///a/file00.ts",
-            "version": 1
-          },
-          "edits": [
-            {
-              "range": {
-                "start": {
-                  "line": 0,
-                  "character": 0
-                },
-                "end": {
-                  "line": 0,
-                  "character": 0
-                }
-              },
-              "newText": "import { DuckConfig } from \"./file01.ts\";\n\n"
-            }
-          ]
-        }
-      ]
-    }
-  }
-]
diff --git a/cli/tests/testdata/lsp/code_action_response_no_disabled.json b/cli/tests/testdata/lsp/code_action_response_no_disabled.json
deleted file mode 100644
index 11d2136b5e3030..00000000000000
--- a/cli/tests/testdata/lsp/code_action_response_no_disabled.json
+++ /dev/null
@@ -1,42 +0,0 @@
-[
-  {
-    "title": "Extract to function in module scope",
-    "kind": "refactor.extract.function",
-    "isPreferred": false,
-    "data": {
-      "specifier": "file:///a/file.ts",
-      "range": {
-        "start": {
-          "line": 0,
-          "character": 0
-        },
-        "end": {
-          "line": 14,
-          "character": 0
-        }
-      },
-      "refactorName": "Extract Symbol",
-      "actionName": "function_scope_0"
-    }
-  },
-  {
-    "title": "Move to a new file",
-    "kind": "refactor.move.newFile",
-    "isPreferred": false,
-    "data": {
-      "specifier": "file:///a/file.ts",
-      "range": {
-        "start": {
-          "line": 0,
-          "character": 0
-        },
-        "end": {
-          "line": 14,
-          "character": 0
-        }
-      },
-      "refactorName": "Move to a new file",
-      "actionName": "Move to a new file"
-    }
-  }
-]
diff --git a/cli/tests/testdata/lsp/code_action_response_refactor.json b/cli/tests/testdata/lsp/code_action_response_refactor.json
deleted file mode 100644
index d0d9fb0ee2e36d..00000000000000
--- a/cli/tests/testdata/lsp/code_action_response_refactor.json
+++ /dev/null
@@ -1,177 +0,0 @@
-[
-  {
-    "title": "Extract to function in module scope",
-    "kind": "refactor.extract.function",
-    "isPreferred": false,
-    "data": {
-      "specifier": "file:///a/file.ts",
-      "range": {
-        "start": {
-          "line": 0,
-          "character": 0
-        },
-        "end": {
-          "line": 1,
-          "character": 0
-        }
-      },
-      "refactorName": "Extract Symbol",
-      "actionName": "function_scope_0"
-    }
-  },
-  {
-    "title": "Extract to constant in enclosing scope",
-    "kind": "refactor.extract.constant",
-    "isPreferred": false,
-    "data": {
-      "specifier": "file:///a/file.ts",
-      "range": {
-        "start": {
-          "line": 0,
-          "character": 0
-        },
-        "end": {
-          "line": 1,
-          "character": 0
-        }
-      },
-      "refactorName": "Extract Symbol",
-      "actionName": "constant_scope_0"
-    }
-  },
-  {
-    "title": "Move to a new file",
-    "kind": "refactor.move.newFile",
-    "isPreferred": false,
-    "data": {
-      "specifier": "file:///a/file.ts",
-      "range": {
-        "start": {
-          "line": 0,
-          "character": 0
-        },
-        "end": {
-          "line": 1,
-          "character": 0
-        }
-      },
-      "refactorName": "Move to a new file",
-      "actionName": "Move to a new file"
-    }
-  },
-  {
-    "title": "Convert default export to named export",
-    "kind": "refactor.rewrite.export.named",
-    "isPreferred": false,
-    "disabled": {
-      "reason": "This file already has a default export"
-    },
-    "data": {
-      "specifier": "file:///a/file.ts",
-      "range": {
-        "start": {
-          "line": 0,
-          "character": 0
-        },
-        "end": {
-          "line": 1,
-          "character": 0
-        }
-      },
-      "refactorName": "Convert export",
-      "actionName": "Convert default export to named export"
-    }
-  },
-  {
-    "title": "Convert named export to default export",
-    "kind": "refactor.rewrite.export.default",
-    "isPreferred": false,
-    "disabled": {
-      "reason": "This file already has a default export"
-    },
-    "data": {
-      "specifier": "file:///a/file.ts",
-      "range": {
-        "start": {
-          "line": 0,
-          "character": 0
-        },
-        "end": {
-          "line": 1,
-          "character": 0
-        }
-      },
-      "refactorName": "Convert export",
-      "actionName": "Convert named export to default export"
-    }
-  },
-  {
-    "title": "Convert namespace import to named imports",
-    "kind": "refactor.rewrite.import.named",
-    "isPreferred": false,
-    "disabled": {
-      "reason": "Selection is not an import declaration."
-    },
-    "data": {
-      "specifier": "file:///a/file.ts",
-      "range": {
-        "start": {
-          "line": 0,
-          "character": 0
-        },
-        "end": {
-          "line": 1,
-          "character": 0
-        }
-      },
-      "refactorName": "Convert import",
-      "actionName": "Convert namespace import to named imports"
-    }
-  },
-  {
-    "title": "Convert named imports to default import",
-    "kind": "refactor.rewrite.import.default",
-    "isPreferred": false,
-    "disabled": {
-      "reason": "Selection is not an import declaration."
-    },
-    "data": {
-      "specifier": "file:///a/file.ts",
-      "range": {
-        "start": {
-          "line": 0,
-          "character": 0
-        },
-        "end": {
-          "line": 1,
-          "character": 0
-        }
-      },
-      "refactorName": "Convert import",
-      "actionName": "Convert named imports to default import"
-    }
-  },
-  {
-    "title": "Convert named imports to namespace import",
-    "kind": "refactor.rewrite.import.namespace",
-    "isPreferred": false,
-    "disabled": {
-      "reason": "Selection is not an import declaration."
-    },
-    "data": {
-      "specifier": "file:///a/file.ts",
-      "range": {
-        "start": {
-          "line": 0,
-          "character": 0
-        },
-        "end": {
-          "line": 1,
-          "character": 0
-        }
-      },
-      "refactorName": "Convert import",
-      "actionName": "Convert named imports to namespace import"
-    }
-  }
-]
diff --git a/cli/tests/testdata/lsp/code_action_update_ignore_lint_params.json b/cli/tests/testdata/lsp/code_action_update_ignore_lint_params.json
deleted file mode 100644
index 8cbf1185f4c06f..00000000000000
--- a/cli/tests/testdata/lsp/code_action_update_ignore_lint_params.json
+++ /dev/null
@@ -1,39 +0,0 @@
-{
-  "textDocument": {
-    "uri": "file:///a/file.ts"
-  },
-  "range": {
-    "start": {
-      "line": 3,
-      "character": 5
-    },
-    "end": {
-      "line": 3,
-      "character": 15
-    }
-  },
-  "context": {
-    "diagnostics": [
-      {
-        "range": {
-          "start": {
-            "line": 3,
-            "character": 5
-          },
-          "end": {
-            "line": 3,
-            "character": 15
-          }
-        },
-        "severity": 1,
-        "code": "prefer-const",
-        "source": "deno-lint",
-        "message": "'snake_case' is never reassigned\nUse 'const' instead",
-        "relatedInformation": []
-      }
-    ],
-    "only": [
-      "quickfix"
-    ]
-  }
-}
diff --git a/cli/tests/testdata/lsp/code_action_update_ignore_lint_response.json b/cli/tests/testdata/lsp/code_action_update_ignore_lint_response.json
deleted file mode 100644
index a23e719e0ceb66..00000000000000
--- a/cli/tests/testdata/lsp/code_action_update_ignore_lint_response.json
+++ /dev/null
@@ -1,92 +0,0 @@
-[
-  {
-    "title": "Disable prefer-const for this line",
-    "kind": "quickfix",
-    "diagnostics": [
-      {
-        "range": {
-          "start": { "line": 3, "character": 5 },
-          "end": { "line": 3, "character": 15 }
-        },
-        "severity": 1,
-        "code": "prefer-const",
-        "source": "deno-lint",
-        "message": "'snake_case' is never reassigned\nUse 'const' instead",
-        "relatedInformation": []
-      }
-    ],
-    "edit": {
-      "changes": {
-        "file:///a/file.ts": [
-          {
-            "range": {
-              "start": { "line": 3, "character": 0 },
-              "end": { "line": 3, "character": 0 }
-            },
-            "newText": "// deno-lint-ignore prefer-const\n"
-          }
-        ]
-      }
-    }
-  },
-  {
-    "title": "Disable prefer-const for the entire file",
-    "kind": "quickfix",
-    "diagnostics": [
-      {
-        "range": {
-          "start": { "line": 3, "character": 5 },
-          "end": { "line": 3, "character": 15 }
-        },
-        "severity": 1,
-        "code": "prefer-const",
-        "source": "deno-lint",
-        "message": "'snake_case' is never reassigned\nUse 'const' instead",
-        "relatedInformation": []
-      }
-    ],
-    "edit": {
-      "changes": {
-        "file:///a/file.ts": [
-          {
-            "range": {
-              "start": { "line": 1, "character": 34 },
-              "end": { "line": 1, "character": 34 }
-            },
-            "newText": " prefer-const"
-          }
-        ]
-      }
-    }
-  },
-  {
-    "title": "Ignore lint errors for the entire file",
-    "kind": "quickfix",
-    "diagnostics": [
-      {
-        "range": {
-          "start": { "line": 3, "character": 5 },
-          "end": { "line": 3, "character": 15 }
-        },
-        "severity": 1,
-        "code": "prefer-const",
-        "source": "deno-lint",
-        "message": "'snake_case' is never reassigned\nUse 'const' instead",
-        "relatedInformation": []
-      }
-    ],
-    "edit": {
-      "changes": {
-        "file:///a/file.ts": [
-          {
-            "range": {
-              "start": { "line": 0, "character": 0 },
-              "end": { "line": 0, "character": 0 }
-            },
-            "newText": "// deno-lint-ignore-file\n"
-          }
-        ]
-      }
-    }
-  }
-]
diff --git a/cli/tests/testdata/lsp/code_actions/cache_npm/cache_action.json b/cli/tests/testdata/lsp/code_actions/cache_npm/cache_action.json
deleted file mode 100644
index b698df3bd8834d..00000000000000
--- a/cli/tests/testdata/lsp/code_actions/cache_npm/cache_action.json
+++ /dev/null
@@ -1,41 +0,0 @@
-{
-  "textDocument": {
-    "uri": "file:///a/file.ts"
-  },
-  "range": {
-    "start": {
-      "line": 0,
-      "character": 18
-    },
-    "end": {
-      "line": 0,
-      "character": 29
-    }
-  },
-  "context": {
-    "diagnostics": [
-      {
-        "range": {
-          "start": {
-            "line": 0,
-            "character": 18
-          },
-          "end": {
-            "line": 0,
-            "character": 29
-          }
-        },
-        "severity": 1,
-        "code": "no-cache-npm",
-        "source": "deno",
-        "message": "Uncached or missing npm package: \"chalk\".",
-        "data": {
-          "specifier": "npm:chalk"
-        }
-      }
-    ],
-    "only": [
-      "quickfix"
-    ]
-  }
-}
diff --git a/cli/tests/testdata/lsp/code_actions/cache_npm/cache_response.json b/cli/tests/testdata/lsp/code_actions/cache_npm/cache_response.json
deleted file mode 100644
index 1b41babcb8ef31..00000000000000
--- a/cli/tests/testdata/lsp/code_actions/cache_npm/cache_response.json
+++ /dev/null
@@ -1,36 +0,0 @@
-[
-  {
-    "title": "Cache \"npm:chalk\" and its dependencies.",
-    "kind": "quickfix",
-    "diagnostics": [
-      {
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-          "start": {
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-          },
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-        },
-        "severity": 1,
-        "code": "no-cache-npm",
-        "source": "deno",
-        "message": "Uncached or missing npm package: \"chalk\".",
-        "data": {
-          "specifier": "npm:chalk"
-        }
-      }
-    ],
-    "command": {
-      "title": "",
-      "command": "deno.cache",
-      "arguments": [
-        [
-          "npm:chalk"
-        ]
-      ]
-    }
-  }
-]
diff --git a/cli/tests/testdata/lsp/code_actions/cache_npm/diagnostics.json b/cli/tests/testdata/lsp/code_actions/cache_npm/diagnostics.json
deleted file mode 100644
index 63c9d0029d5215..00000000000000
--- a/cli/tests/testdata/lsp/code_actions/cache_npm/diagnostics.json
+++ /dev/null
@@ -1,25 +0,0 @@
-{
-  "uri": "file:///a/file.ts",
-  "diagnostics": [
-    {
-      "range": {
-        "start": {
-          "line": 0,
-          "character": 18
-        },
-        "end": {
-          "line": 0,
-          "character": 29
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-      "severity": 1,
-      "code": "no-cache-npm",
-      "source": "deno",
-      "message": "Uncached or missing npm package: \"chalk\".",
-      "data": {
-        "specifier": "npm:chalk"
-      }
-    }
-  ],
-  "version": 1
-}
diff --git a/cli/tests/testdata/lsp/code_lens_resolve_response.json b/cli/tests/testdata/lsp/code_lens_resolve_response.json
deleted file mode 100644
index a958b4db4d00cd..00000000000000
--- a/cli/tests/testdata/lsp/code_lens_resolve_response.json
+++ /dev/null
@@ -1,51 +0,0 @@
-{
-  "range": {
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-      "line": 0,
-      "character": 6
-    },
-    "end": {
-      "line": 0,
-      "character": 7
-    }
-  },
-  "command": {
-    "title": "2 references",
-    "command": "deno.showReferences",
-    "arguments": [
-      "file:///a/file.ts",
-      {
-        "line": 0,
-        "character": 6
-      },
-      [
-        {
-          "uri": "file:///a/file.ts",
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-            },
-            "end": {
-              "line": 0,
-              "character": 7
-            }
-          }
-        },
-        {
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-          "range": {
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-            "end": {
-              "line": 12,
-              "character": 15
-            }
-          }
-        }
-      ]
-    ]
-  }
-}
diff --git a/cli/tests/testdata/lsp/code_lens_resolve_response_impl.json b/cli/tests/testdata/lsp/code_lens_resolve_response_impl.json
deleted file mode 100644
index cabf2f8334be8d..00000000000000
--- a/cli/tests/testdata/lsp/code_lens_resolve_response_impl.json
+++ /dev/null
@@ -1,38 +0,0 @@
-{
-  "range": {
-    "start": {
-      "line": 0,
-      "character": 10
-    },
-    "end": {
-      "line": 0,
-      "character": 11
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-  },
-  "command": {
-    "title": "1 implementation",
-    "command": "deno.showReferences",
-    "arguments": [
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-      {
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-      [
-        {
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-          "range": {
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-              "character": 6
-            },
-            "end": {
-              "line": 4,
-              "character": 7
-            }
-          }
-        }
-      ]
-    ]
-  }
-}
diff --git a/cli/tests/testdata/lsp/code_lens_response.json b/cli/tests/testdata/lsp/code_lens_response.json
deleted file mode 100644
index e3a87e4be631e3..00000000000000
--- a/cli/tests/testdata/lsp/code_lens_response.json
+++ /dev/null
@@ -1,34 +0,0 @@
-[
-  {
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-        "line": 0,
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-    "data": {
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-      "source": "references"
-    }
-  },
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-      }
-    },
-    "data": {
-      "specifier": "file:///a/file.ts",
-      "source": "references"
-    }
-  }
-]
diff --git a/cli/tests/testdata/lsp/code_lens_response_changed.json b/cli/tests/testdata/lsp/code_lens_response_changed.json
deleted file mode 100644
index b0073a23f7c36c..00000000000000
--- a/cli/tests/testdata/lsp/code_lens_response_changed.json
+++ /dev/null
@@ -1,50 +0,0 @@
-[
-  {
-    "range": {
-      "start": {
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-        "character": 10
-      },
-      "end": {
-        "line": 0,
-        "character": 11
-      }
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-    "data": {
-      "specifier": "file:///a/file.ts",
-      "source": "implementations"
-    }
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-  {
-    "range": {
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-    "data": {
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-      "source": "references"
-    }
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-      "start": {
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-      "end": {
-        "line": 4,
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-      }
-    },
-    "data": {
-      "specifier": "file:///a/file.ts",
-      "source": "references"
-    }
-  }
-]
diff --git a/cli/tests/testdata/lsp/code_lens_response_impl.json b/cli/tests/testdata/lsp/code_lens_response_impl.json
deleted file mode 100644
index c6e5bd92d3e868..00000000000000
--- a/cli/tests/testdata/lsp/code_lens_response_impl.json
+++ /dev/null
@@ -1,98 +0,0 @@
-[
-  {
-    "range": {
-      "start": {
-        "line": 0,
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-      },
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-        "line": 0,
-        "character": 11
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-      "specifier": "file:///a/file.ts",
-      "source": "implementations"
-    }
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-      "source": "references"
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-      "source": "references"
-    }
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-    "range": {
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-      "source": "implementations"
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-  {
-    "range": {
-      "start": {
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-        "character": 10
-      },
-      "end": {
-        "line": 10,
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-      }
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-    "data": {
-      "specifier": "file:///a/file.ts",
-      "source": "references"
-    }
-  },
-  {
-    "range": {
-      "start": {
-        "line": 11,
-        "character": 2
-      },
-      "end": {
-        "line": 11,
-        "character": 3
-      }
-    },
-    "data": {
-      "specifier": "file:///a/file.ts",
-      "source": "references"
-    }
-  }
-]
diff --git a/cli/tests/testdata/lsp/code_lens_response_test.json b/cli/tests/testdata/lsp/code_lens_response_test.json
deleted file mode 100644
index 159839816c860c..00000000000000
--- a/cli/tests/testdata/lsp/code_lens_response_test.json
+++ /dev/null
@@ -1,370 +0,0 @@
-[
-  {
-    "range": {
-      "start": {
-        "line": 4,
-        "character": 5
-      },
-      "end": {
-        "line": 4,
-        "character": 9
-      }
-    },
-    "command": {
-      "title": "▶︎ Run Test",
-      "command": "deno.test",
-      "arguments": [
-        "file:///a/file.ts",
-        "test a",
-        {
-          "inspect": false
-        }
-      ]
-    }
-  },
-  {
-    "range": {
-      "start": {
-        "line": 4,
-        "character": 5
-      },
-      "end": {
-        "line": 4,
-        "character": 9
-      }
-    },
-    "command": {
-      "title": "Debug",
-      "command": "deno.test",
-      "arguments": [
-        "file:///a/file.ts",
-        "test a",
-        {
-          "inspect": true
-        }
-      ]
-    }
-  },
-  {
-    "range": {
-      "start": {
-        "line": 5,
-        "character": 5
-      },
-      "end": {
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-      }
-    },
-    "command": {
-      "title": "▶︎ Run Test",
-      "command": "deno.test",
-      "arguments": [
-        "file:///a/file.ts",
-        "test b",
-        {
-          "inspect": false
-        }
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-    }
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-      "end": {
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-      }
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-    "command": {
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-        "file:///a/file.ts",
-        "test c",
-        {
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-        }
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-    "command": {
-      "title": "Debug",
-      "command": "deno.test",
-      "arguments": [
-        "file:///a/file.ts",
-        "test c",
-        {
-          "inspect": true
-        }
-      ]
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-  },
-  {
-    "range": {
-      "start": {
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-        "character": 0
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-      "end": {
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-        "character": 4
-      }
-    },
-    "command": {
-      "title": "▶︎ Run Test",
-      "command": "deno.test",
-      "arguments": [
-        "file:///a/file.ts",
-        "test d",
-        {
-          "inspect": false
-        }
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-    }
-  },
-  {
-    "range": {
-      "start": {
-        "line": 13,
-        "character": 0
-      },
-      "end": {
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-        "character": 4
-      }
-    },
-    "command": {
-      "title": "Debug",
-      "command": "deno.test",
-      "arguments": [
-        "file:///a/file.ts",
-        "test d",
-        {
-          "inspect": true
-        }
-      ]
-    }
-  },
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-        "character": 0
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-      "end": {
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-      }
-    },
-    "command": {
-      "title": "▶︎ Run Test",
-      "command": "deno.test",
-      "arguments": [
-        "file:///a/file.ts",
-        "test e",
-        {
-          "inspect": false
-        }
-      ]
-    }
-  },
-  {
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-      "start": {
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-        "character": 0
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-    "command": {
-      "title": "Debug",
-      "command": "deno.test",
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-        "test e",
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-        }
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-    "command": {
-      "title": "▶︎ Run Test",
-      "command": "deno.test",
-      "arguments": [
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-        "test f",
-        {
-          "inspect": false
-        }
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-    }
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-      "title": "Debug",
-      "command": "deno.test",
-      "arguments": [
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-        "test f",
-        {
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-        }
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-    }
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-      "command": "deno.test",
-      "arguments": [
-        "file:///a/file.ts",
-        "test g",
-        {
-          "inspect": false
-        }
-      ]
-    }
-  },
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-        "character": 0
-      },
-      "end": {
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-        "character": 5
-      }
-    },
-    "command": {
-      "title": "Debug",
-      "command": "deno.test",
-      "arguments": [
-        "file:///a/file.ts",
-        "test g",
-        {
-          "inspect": true
-        }
-      ]
-    }
-  },
-  {
-    "range": {
-      "start": {
-        "line": 23,
-        "character": 0
-      },
-      "end": {
-        "line": 23,
-        "character": 5
-      }
-    },
-    "command": {
-      "title": "▶︎ Run Test",
-      "command": "deno.test",
-      "arguments": [
-        "file:///a/file.ts",
-        "test h",
-        {
-          "inspect": false
-        }
-      ]
-    }
-  },
-  {
-    "range": {
-      "start": {
-        "line": 23,
-        "character": 0
-      },
-      "end": {
-        "line": 23,
-        "character": 5
-      }
-    },
-    "command": {
-      "title": "Debug",
-      "command": "deno.test",
-      "arguments": [
-        "file:///a/file.ts",
-        "test h",
-        {
-          "inspect": true
-        }
-      ]
-    }
-  }
-]
diff --git a/cli/tests/testdata/lsp/completion_request_params_optional.json b/cli/tests/testdata/lsp/completion_request_params_optional.json
deleted file mode 100644
index 1f3c079c738d82..00000000000000
--- a/cli/tests/testdata/lsp/completion_request_params_optional.json
+++ /dev/null
@@ -1,13 +0,0 @@
-{
-  "textDocument": {
-    "uri": "file:///a/file.ts"
-  },
-  "position": {
-    "line": 8,
-    "character": 4
-  },
-  "context": {
-    "triggerKind": 2,
-    "triggerCharacter": "."
-  }
-}
diff --git a/cli/tests/testdata/lsp/completion_request_response_empty.json b/cli/tests/testdata/lsp/completion_request_response_empty.json
deleted file mode 100644
index 9ece16e909606d..00000000000000
--- a/cli/tests/testdata/lsp/completion_request_response_empty.json
+++ /dev/null
@@ -1,51 +0,0 @@
-{
-  "isIncomplete": false,
-  "items": [
-    {
-      "label": ".",
-      "kind": 19,
-      "detail": "(local)",
-      "sortText": "1",
-      "insertText": ".",
-      "commitCharacters": [
-        "\"",
-        "'"
-      ]
-    },
-    {
-      "label": "..",
-      "kind": 19,
-      "detail": "(local)",
-      "sortText": "1",
-      "insertText": "..",
-      "commitCharacters": [
-        "\"",
-        "'"
-      ]
-    },
-    {
-      "label": "http://localhost:4545",
-      "kind": 19,
-      "detail": "(registry)",
-      "sortText": "2",
-      "textEdit": {
-        "range": {
-          "start": {
-            "line": 0,
-            "character": 20
-          },
-          "end": {
-            "line": 0,
-            "character": 20
-          }
-        },
-        "newText": "http://localhost:4545"
-      },
-      "commitCharacters": [
-        "\"",
-        "'",
-        "/"
-      ]
-    }
-  ]
-}
diff --git a/cli/tests/testdata/lsp/completion_resolve_params.json b/cli/tests/testdata/lsp/completion_resolve_params.json
deleted file mode 100644
index 26231036da156f..00000000000000
--- a/cli/tests/testdata/lsp/completion_resolve_params.json
+++ /dev/null
@@ -1,14 +0,0 @@
-{
-  "label": "build",
-  "kind": 6,
-  "sortText": "1",
-  "insertTextFormat": 1,
-  "data": {
-    "tsc": {
-      "specifier": "file:///a/file.ts",
-      "position": 5,
-      "name": "build",
-      "useCodeSnippet": false
-    }
-  }
-}
diff --git a/cli/tests/testdata/lsp/completion_resolve_params_optional.json b/cli/tests/testdata/lsp/completion_resolve_params_optional.json
deleted file mode 100644
index cb99bf960cc030..00000000000000
--- a/cli/tests/testdata/lsp/completion_resolve_params_optional.json
+++ /dev/null
@@ -1,15 +0,0 @@
-{
-  "label": "b?",
-  "kind": 5,
-  "sortText": "1",
-  "filterText": "b",
-  "insertText": "b",
-  "data": {
-    "tsc": {
-      "specifier": "file:///a/file.ts",
-      "position": 79,
-      "name": "b",
-      "useCodeSnippet": false
-    }
-  }
-}
diff --git a/cli/tests/testdata/lsp/completion_resolve_params_registry.json b/cli/tests/testdata/lsp/completion_resolve_params_registry.json
deleted file mode 100644
index 99a4a048e2646e..00000000000000
--- a/cli/tests/testdata/lsp/completion_resolve_params_registry.json
+++ /dev/null
@@ -1,20 +0,0 @@
-{
-  "label": "v2.0.0",
-  "kind": 19,
-  "detail": "(version)",
-  "sortText": "0000000003",
-  "filterText": "http://localhost:4545/x/a@v2.0.0",
-  "textEdit": {
-    "range": {
-      "start": {
-        "line": 0,
-        "character": 20
-      },
-      "end": {
-        "line": 0,
-        "character": 46
-      }
-    },
-    "newText": "http://localhost:4545/x/a@v2.0.0"
-  }
-}
diff --git a/cli/tests/testdata/lsp/completion_resolve_response.json b/cli/tests/testdata/lsp/completion_resolve_response.json
deleted file mode 100644
index 28ad756a332e01..00000000000000
--- a/cli/tests/testdata/lsp/completion_resolve_response.json
+++ /dev/null
@@ -1,11 +0,0 @@
-{
-  "label": "build",
-  "kind": 6,
-  "detail": "const Deno.build: {\n    target: string;\n    arch: \"x86_64\" | \"aarch64\";\n    os: \"darwin\" | \"linux\" | \"windows\" | \"freebsd\" | \"netbsd\" | \"aix\" | \"solaris\" | \"illumos\";\n    vendor: string;\n    env?: string | undefined;\n}",
-  "documentation": {
-    "kind": "markdown",
-    "value": "Information related to the build of the current Deno runtime.\n\nUsers are discouraged from code branching based on this information, as\nassumptions about what is available in what build environment might change\nover time. Developers should specifically sniff out the features they\nintend to use.\n\nThe intended use for the information is for logging and debugging purposes.\n\n*@category* - Runtime Environment"
-  },
-  "sortText": "1",
-  "insertTextFormat": 1
-}
diff --git a/cli/tests/testdata/lsp/completion_resolve_response_registry.json b/cli/tests/testdata/lsp/completion_resolve_response_registry.json
deleted file mode 100644
index 99a4a048e2646e..00000000000000
--- a/cli/tests/testdata/lsp/completion_resolve_response_registry.json
+++ /dev/null
@@ -1,20 +0,0 @@
-{
-  "label": "v2.0.0",
-  "kind": 19,
-  "detail": "(version)",
-  "sortText": "0000000003",
-  "filterText": "http://localhost:4545/x/a@v2.0.0",
-  "textEdit": {
-    "range": {
-      "start": {
-        "line": 0,
-        "character": 20
-      },
-      "end": {
-        "line": 0,
-        "character": 46
-      }
-    },
-    "newText": "http://localhost:4545/x/a@v2.0.0"
-  }
-}
diff --git a/cli/tests/testdata/lsp/completions/npm/resolve_params.json b/cli/tests/testdata/lsp/completions/npm/resolve_params.json
deleted file mode 100644
index c83b8ce495832d..00000000000000
--- a/cli/tests/testdata/lsp/completions/npm/resolve_params.json
+++ /dev/null
@@ -1,14 +0,0 @@
-{
-  "label": "MyClass",
-  "kind": 6,
-  "sortText": "1",
-  "insertTextFormat": 1,
-  "data": {
-    "tsc": {
-      "specifier": "file:///a/file.ts",
-      "position": 69,
-      "name": "MyClass",
-      "useCodeSnippet": false
-    }
-  }
-}
diff --git a/cli/tests/testdata/lsp/completions/npm/resolve_response.json b/cli/tests/testdata/lsp/completions/npm/resolve_response.json
deleted file mode 100644
index c83b8ce495832d..00000000000000
--- a/cli/tests/testdata/lsp/completions/npm/resolve_response.json
+++ /dev/null
@@ -1,14 +0,0 @@
-{
-  "label": "MyClass",
-  "kind": 6,
-  "sortText": "1",
-  "insertTextFormat": 1,
-  "data": {
-    "tsc": {
-      "specifier": "file:///a/file.ts",
-      "position": 69,
-      "name": "MyClass",
-      "useCodeSnippet": false
-    }
-  }
-}
diff --git a/cli/tests/testdata/lsp/deno.embedded_import_map.jsonc b/cli/tests/testdata/lsp/deno.embedded_import_map.jsonc
deleted file mode 100644
index 75d5d08491836f..00000000000000
--- a/cli/tests/testdata/lsp/deno.embedded_import_map.jsonc
+++ /dev/null
@@ -1,5 +0,0 @@
-{
-  "imports": {
-    "/~/": "./lib/"
-  }
-}
diff --git a/cli/tests/testdata/lsp/deno.fmt.exclude.jsonc b/cli/tests/testdata/lsp/deno.fmt.exclude.jsonc
deleted file mode 100644
index 246a403168d58f..00000000000000
--- a/cli/tests/testdata/lsp/deno.fmt.exclude.jsonc
+++ /dev/null
@@ -1,16 +0,0 @@
-{
-  "fmt": {
-    "files": {
-      "exclude": [
-        "ignored.ts"
-      ]
-    },
-    "options": {
-      "useTabs": true,
-      "lineWidth": 40,
-      "indentWidth": 8,
-      "singleQuote": true,
-      "proseWrap": "always"
-    }
-  }
-}
diff --git a/cli/tests/testdata/lsp/deno.fmt.jsonc b/cli/tests/testdata/lsp/deno.fmt.jsonc
deleted file mode 100644
index a0a8517318b7d2..00000000000000
--- a/cli/tests/testdata/lsp/deno.fmt.jsonc
+++ /dev/null
@@ -1,11 +0,0 @@
-{
-  "fmt": {
-    "options": {
-      "useTabs": true,
-      "lineWidth": 40,
-      "indentWidth": 8,
-      "singleQuote": true,
-      "proseWrap": "always"
-    }
-  }
-}
diff --git a/cli/tests/testdata/lsp/deno.lint.jsonc b/cli/tests/testdata/lsp/deno.lint.jsonc
deleted file mode 100644
index 03308ab5f9acbd..00000000000000
--- a/cli/tests/testdata/lsp/deno.lint.jsonc
+++ /dev/null
@@ -1,13 +0,0 @@
-{
-  "lint": {
-    "rules": {
-      "exclude": [
-        "camelcase"
-      ],
-      "include": [
-        "ban-untagged-todo"
-      ],
-      "tags": []
-    }
-  }
-}
diff --git a/cli/tests/testdata/lsp/diagnostics_deno_deps.json b/cli/tests/testdata/lsp/diagnostics_deno_deps.json
deleted file mode 100644
index ec6cc4f516b652..00000000000000
--- a/cli/tests/testdata/lsp/diagnostics_deno_deps.json
+++ /dev/null
@@ -1,25 +0,0 @@
-{
-  "uri": "file:///a/file.ts",
-  "diagnostics": [
-    {
-      "range": {
-        "start": {
-          "line": 0,
-          "character": 19
-        },
-        "end": {
-          "line": 0,
-          "character": 49
-        }
-      },
-      "severity": 1,
-      "code": "no-cache",
-      "source": "deno",
-      "message": "Uncached or missing remote URL: \"https://deno.land/x/a/mod.ts\".",
-      "data": {
-        "specifier": "https://deno.land/x/a/mod.ts"
-      }
-    }
-  ],
-  "version": 1
-}
diff --git a/cli/tests/testdata/lsp/did_open_lint.json b/cli/tests/testdata/lsp/did_open_lint.json
deleted file mode 100644
index 51cef98077ea4a..00000000000000
--- a/cli/tests/testdata/lsp/did_open_lint.json
+++ /dev/null
@@ -1,8 +0,0 @@
-{
-  "textDocument": {
-    "uri": "file:///a/file.ts",
-    "languageId": "typescript",
-    "version": 1,
-    "text": "// TODO: fixme\nexport async function non_camel_case() {\nconsole.log(\"finished!\")\n}"
-  }
-}
diff --git a/cli/tests/testdata/lsp/did_open_params_deno_types.json b/cli/tests/testdata/lsp/did_open_params_deno_types.json
deleted file mode 100644
index 6f085d04549076..00000000000000
--- a/cli/tests/testdata/lsp/did_open_params_deno_types.json
+++ /dev/null
@@ -1,8 +0,0 @@
-{
-  "textDocument": {
-    "uri": "file:///a/file.ts",
-    "languageId": "typescript",
-    "version": 1,
-    "text": "/// <reference types=\"https://example.com/a/b.d.ts\" />\n/// <reference path=\"https://example.com/a/c.ts\"\n\n// @deno-types=https://example.com/a/d.d.ts\nimport * as d from \"https://example.com/a/d.js\";\n\n// @deno-types=\"https://example.com/a/e.d.ts\"\nimport * as e from \"https://example.com/a/e.js\";\n\nconsole.log(d, e);\n"
-  }
-}
diff --git a/cli/tests/testdata/lsp/did_open_params_doc_symbol.json b/cli/tests/testdata/lsp/did_open_params_doc_symbol.json
deleted file mode 100644
index c748771919e1ea..00000000000000
--- a/cli/tests/testdata/lsp/did_open_params_doc_symbol.json
+++ /dev/null
@@ -1,8 +0,0 @@
-{
-  "textDocument": {
-    "uri": "file:///a/file.ts",
-    "languageId": "typescript",
-    "version": 1,
-    "text": "interface IFoo {\n  foo(): boolean;\n}\n\nclass Bar implements IFoo {\n  constructor(public x: number) { }\n  foo() { return true; }\n  /** @deprecated */\n  baz() { return false; }\n  get value(): number { return 0; }\n  set value(newVavlue: number) { return; }\n  static staticBar = new Bar(0);\n  private static getStaticBar() { return Bar.staticBar; }\n}\n\nenum Values { value1, value2 }\n\nvar bar: IFoo = new Bar(3);"
-  }
-}
diff --git a/cli/tests/testdata/lsp/did_open_params_import_hover.json b/cli/tests/testdata/lsp/did_open_params_import_hover.json
deleted file mode 100644
index a79ba0d7fce833..00000000000000
--- a/cli/tests/testdata/lsp/did_open_params_import_hover.json
+++ /dev/null
@@ -1,8 +0,0 @@
-{
-  "textDocument": {
-    "uri": "file:///a/file.ts",
-    "languageId": "typescript",
-    "version": 1,
-    "text": "import * as a from \"http://127.0.0.1:4545/xTypeScriptTypes.js\";\n// @deno-types=\"http://127.0.0.1:4545/type_definitions/foo.d.ts\"\nimport * as b from \"http://127.0.0.1:4545/type_definitions/foo.js\";\nimport * as c from \"http://127.0.0.1:4545/subdir/type_reference.js\";\nimport * as d from \"http://127.0.0.1:4545/subdir/mod1.ts\";\nimport * as e from \"data:application/typescript;base64,ZXhwb3J0IGNvbnN0IGEgPSAiYSI7CgpleHBvcnQgZW51bSBBIHsKICBBLAogIEIsCiAgQywKfQo=\";\nimport * as f from \"./file_01.ts\";\nimport * as g from \"http://localhost:4545/x/a/mod.ts\";\n\nconsole.log(a, b, c, d, e, f, g);\n"
-  }
-}
diff --git a/cli/tests/testdata/lsp/did_open_params_large.json b/cli/tests/testdata/lsp/did_open_params_large.json
deleted file mode 100644
index 0347ab67b27bbf..00000000000000
--- a/cli/tests/testdata/lsp/did_open_params_large.json
+++ /dev/null
@@ -1,8 +0,0 @@
-{
-  "textDocument": {
-    "uri": "file:///a/file.ts",
-    "languageId": "javascript",
-    "version": 1,
-    "text": "// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.\n\n// @ts-check\n/// <reference path=\"./compiler.d.ts\" />\n// deno-lint-ignore-file no-undef\n\n// This module is the entry point for \"compiler\" isolate, ie. the one\n// that is created when Deno needs to type check TypeScript, and in some\n// instances convert TypeScript to JavaScript.\n\n// Removes the `__proto__` for security reasons.  This intentionally makes\n// Deno non compliant with ECMA-262 Annex B.2.2.1\ndelete Object.prototype.__proto__;\n\n((window) => {\n  /** @type {DenoCore} */\n  const core = window.Deno.core;\n\n  let logDebug = false;\n  let logSource = \"JS\";\n\n  function setLogDebug(debug, source) {\n    logDebug = debug;\n    if (source) {\n      logSource = source;\n    }\n  }\n\n  function debug(...args) {\n    if (logDebug) {\n      const stringifiedArgs = args.map((arg) =>\n        typeof arg === \"string\" ? arg : JSON.stringify(arg)\n      ).join(\" \");\n      // adding a non-zero integer value to the end of the debug string causes\n      // the message to be printed to stderr instead of stdout, which is better\n      // aligned to the behaviour of debug messages\n      core.print(`DEBUG ${logSource} - ${stringifiedArgs}\\n`, 1);\n    }\n  }\n\n  function error(...args) {\n    const stringifiedArgs = args.map((arg) =>\n      typeof arg === \"string\" || arg instanceof Error\n        ? String(arg)\n        : JSON.stringify(arg)\n    ).join(\" \");\n    core.print(`ERROR ${logSource} = ${stringifiedArgs}\\n`, 1);\n  }\n\n  class AssertionError extends Error {\n    constructor(msg) {\n      super(msg);\n      this.name = \"AssertionError\";\n    }\n  }\n\n  function assert(cond, msg = \"Assertion failed.\") {\n    if (!cond) {\n      throw new AssertionError(msg);\n    }\n  }\n\n  /** @type {Map<string, ts.SourceFile>} */\n  const sourceFileCache = new Map();\n\n  /** @param {ts.DiagnosticRelatedInformation} diagnostic */\n  function fromRelatedInformation({\n    start,\n    length,\n    file,\n    messageText: msgText,\n    ...ri\n  }) {\n    let messageText;\n    let messageChain;\n    if (typeof msgText === \"object\") {\n      messageChain = msgText;\n    } else {\n      messageText = msgText;\n    }\n    if (start !== undefined && length !== undefined && file) {\n      const startPos = file.getLineAndCharacterOfPosition(start);\n      const sourceLine = file.getFullText().split(\"\\n\")[startPos.line];\n      const fileName = file.fileName;\n      return {\n        start: startPos,\n        end: file.getLineAndCharacterOfPosition(start + length),\n        fileName,\n        messageChain,\n        messageText,\n        sourceLine,\n        ...ri,\n      };\n    } else {\n      return {\n        messageChain,\n        messageText,\n        ...ri,\n      };\n    }\n  }\n\n  /** @param {ts.Diagnostic[]} diagnostics */\n  function fromTypeScriptDiagnostic(diagnostics) {\n    return diagnostics.map(({ relatedInformation: ri, source, ...diag }) => {\n      /** @type {any} */\n      const value = fromRelatedInformation(diag);\n      value.relatedInformation = ri\n        ? ri.map(fromRelatedInformation)\n        : undefined;\n      value.source = source;\n      return value;\n    });\n  }\n\n  // Using incremental compile APIs requires that all\n  // paths must be either relative or absolute. Since\n  // analysis in Rust operates on fully resolved URLs,\n  // it makes sense to use the same scheme here.\n  const ASSETS = \"asset:///\";\n  const CACHE = \"cache:///\";\n\n  /** Diagnostics that are intentionally ignored when compiling TypeScript in\n   * Deno, as they provide misleading or incorrect information. */\n  const IGNORED_DIAGNOSTICS = [\n    // TS1208: All files must be modules when the '--isolatedModules' flag is\n    // provided.  We can ignore because we guarantee that all files are\n    // modules.\n    1208,\n    // TS1375: 'await' expressions are only allowed at the top level of a file\n    // when that file is a module, but this file has no imports or exports.\n    // Consider adding an empty 'export {}' to make this file a module.\n    1375,\n    // TS1103: 'for-await-of' statement is only allowed within an async function\n    // or async generator.\n    1103,\n    // TS2306: File 'file:///Users/rld/src/deno/subdir/amd_like.js' is\n    // not a module.\n    2306,\n    // TS2691: An import path cannot end with a '.ts' extension. Consider\n    // importing 'bad-module' instead.\n    2691,\n    // TS2792: Cannot find module. Did you mean to set the 'moduleResolution'\n    // option to 'node', or to add aliases to the 'paths' option?\n    2792,\n    // TS5009: Cannot find the common subdirectory path for the input files.\n    5009,\n    // TS5055: Cannot write file\n    // 'http://localhost:4545/subdir/mt_application_x_javascript.j4.js'\n    // because it would overwrite input file.\n    5055,\n    // TypeScript is overly opinionated that only CommonJS modules kinds can\n    // support JSON imports.  Allegedly this was fixed in\n    // Microsoft/TypeScript#26825 but that doesn't seem to be working here,\n    // so we will ignore complaints about this compiler setting.\n    5070,\n    // TS7016: Could not find a declaration file for module '...'. '...'\n    // implicitly has an 'any' type.  This is due to `allowJs` being off by\n    // default but importing of a JavaScript module.\n    7016,\n  ];\n\n  const SNAPSHOT_COMPILE_OPTIONS = {\n    esModuleInterop: true,\n    jsx: ts.JsxEmit.React,\n    module: ts.ModuleKind.ESNext,\n    noEmit: true,\n    strict: true,\n    target: ts.ScriptTarget.ESNext,\n  };\n\n  class ScriptSnapshot {\n    /** @type {string} */\n    specifier;\n    /** @type {string} */\n    version;\n    /**\n     * @param {string} specifier\n     * @param {string} version \n     */\n    constructor(specifier, version) {\n      this.specifier = specifier;\n      this.version = version;\n    }\n    /**\n     * @param {number} start \n     * @param {number} end \n     * @returns {string}\n     */\n    getText(start, end) {\n      const { specifier, version } = this;\n      debug(\n        `snapshot.getText(${start}, ${end}) specifier: ${specifier} version: ${version}`,\n      );\n      return core.jsonOpSync(\"op_get_text\", { specifier, version, start, end });\n    }\n    /**\n     * @returns {number}\n     */\n    getLength() {\n      const { specifier, version } = this;\n      debug(`snapshot.getLength() specifier: ${specifier} version: ${version}`);\n      return core.jsonOpSync(\"op_get_length\", { specifier, version });\n    }\n    /**\n     * @param {ScriptSnapshot} oldSnapshot\n     * @returns {ts.TextChangeRange | undefined}\n     */\n    getChangeRange(oldSnapshot) {\n      const { specifier, version } = this;\n      const { version: oldVersion } = oldSnapshot;\n      const oldLength = oldSnapshot.getLength();\n      debug(\n        `snapshot.getLength() specifier: ${specifier} oldVersion: ${oldVersion} version: ${version}`,\n      );\n      return core.jsonOpSync(\n        \"op_get_change_range\",\n        { specifier, oldLength, oldVersion, version },\n      );\n    }\n    dispose() {\n      const { specifier, version } = this;\n      debug(`snapshot.dispose() specifier: ${specifier} version: ${version}`);\n      core.jsonOpSync(\"op_dispose\", { specifier, version });\n    }\n  }\n\n  /** @type {ts.CompilerOptions} */\n  let compilationSettings = {};\n\n  /** @type {ts.LanguageService} */\n  let languageService;\n\n  /** An object literal of the incremental compiler host, which provides the\n   * specific \"bindings\" to the Deno environment that tsc needs to work.\n   *\n   * @type {ts.CompilerHost & ts.LanguageServiceHost} */\n  const host = {\n    fileExists(fileName) {\n      debug(`host.fileExists(\"${fileName}\")`);\n      return false;\n    },\n    readFile(specifier) {\n      debug(`host.readFile(\"${specifier}\")`);\n      return core.jsonOpSync(\"op_load\", { specifier }).data;\n    },\n    getSourceFile(\n      specifier,\n      languageVersion,\n      _onError,\n      _shouldCreateNewSourceFile,\n    ) {\n      debug(\n        `host.getSourceFile(\"${specifier}\", ${\n          ts.ScriptTarget[languageVersion]\n        })`,\n      );\n      let sourceFile = sourceFileCache.get(specifier);\n      if (sourceFile) {\n        return sourceFile;\n      }\n\n      /** @type {{ data: string; hash?: string; scriptKind: ts.ScriptKind }} */\n      const { data, hash, scriptKind } = core.jsonOpSync(\n        \"op_load\",\n        { specifier },\n      );\n      assert(\n        data != null,\n        `\"data\" is unexpectedly null for \"${specifier}\".`,\n      );\n      sourceFile = ts.createSourceFile(\n        specifier,\n        data,\n        languageVersion,\n        false,\n        scriptKind,\n      );\n      sourceFile.moduleName = specifier;\n      sourceFile.version = hash;\n      sourceFileCache.set(specifier, sourceFile);\n      return sourceFile;\n    },\n    getDefaultLibFileName() {\n      return `${ASSETS}/lib.esnext.d.ts`;\n    },\n    getDefaultLibLocation() {\n      return ASSETS;\n    },\n    writeFile(fileName, data, _writeByteOrderMark, _onError, sourceFiles) {\n      debug(`host.writeFile(\"${fileName}\")`);\n      let maybeSpecifiers;\n      if (sourceFiles) {\n        maybeSpecifiers = sourceFiles.map((sf) => sf.moduleName);\n      }\n      return core.jsonOpSync(\n        \"op_emit\",\n        { maybeSpecifiers, fileName, data },\n      );\n    },\n    getCurrentDirectory() {\n      return CACHE;\n    },\n    getCanonicalFileName(fileName) {\n      return fileName;\n    },\n    useCaseSensitiveFileNames() {\n      return true;\n    },\n    getNewLine() {\n      return \"\\n\";\n    },\n    resolveModuleNames(specifiers, base) {\n      debug(`host.resolveModuleNames()`);\n      debug(`  base: ${base}`);\n      debug(`  specifiers: ${specifiers.join(\", \")}`);\n      /** @type {Array<[string, ts.Extension] | undefined>} */\n      const resolved = core.jsonOpSync(\"op_resolve\", {\n        specifiers,\n        base,\n      });\n      if (resolved) {\n        const result = resolved.map((item) => {\n          if (item) {\n            const [resolvedFileName, extension] = item;\n            return {\n              resolvedFileName,\n              extension,\n              isExternalLibraryImport: false,\n            };\n          }\n          return undefined;\n        });\n        result.length = specifiers.length;\n        return result;\n      } else {\n        return new Array(specifiers.length);\n      }\n    },\n    createHash(data) {\n      return core.jsonOpSync(\"op_create_hash\", { data }).hash;\n    },\n\n    // LanguageServiceHost\n    getCompilationSettings() {\n      debug(\"host.getCompilationSettings()\");\n      return compilationSettings;\n    },\n    getScriptFileNames() {\n      debug(\"host.getScriptFileNames()\");\n      return core.jsonOpSync(\"op_script_names\", undefined);\n    },\n    getScriptVersion(specifier) {\n      debug(`host.getScriptVersion(\"${specifier}\")`);\n      const sourceFile = sourceFileCache.get(specifier);\n      if (sourceFile) {\n        return sourceFile.version ?? \"1\";\n      }\n      return core.jsonOpSync(\"op_script_version\", { specifier });\n    },\n    getScriptSnapshot(specifier) {\n      debug(`host.getScriptSnapshot(\"${specifier}\")`);\n      const sourceFile = sourceFileCache.get(specifier);\n      if (sourceFile) {\n        return {\n          getText(start, end) {\n            return sourceFile.text.substring(start, end);\n          },\n          getLength() {\n            return sourceFile.text.length;\n          },\n          getChangeRange() {\n            return undefined;\n          },\n        };\n      }\n      /** @type {string | undefined} */\n      const version = core.jsonOpSync(\"op_script_version\", { specifier });\n      if (version != null) {\n        return new ScriptSnapshot(specifier, version);\n      }\n      return undefined;\n    },\n  };\n\n  /** @type {Array<[string, number]>} */\n  const stats = [];\n  let statsStart = 0;\n\n  function performanceStart() {\n    stats.length = 0;\n    statsStart = Date.now();\n    ts.performance.enable();\n  }\n\n  /**\n   * @param {{ program: ts.Program | ts.EmitAndSemanticDiagnosticsBuilderProgram, fileCount?: number }} options \n   */\n  function performanceProgram({ program, fileCount }) {\n    if (program) {\n      if (\"getProgram\" in program) {\n        program = program.getProgram();\n      }\n      stats.push([\"Files\", program.getSourceFiles().length]);\n      stats.push([\"Nodes\", program.getNodeCount()]);\n      stats.push([\"Identifiers\", program.getIdentifierCount()]);\n      stats.push([\"Symbols\", program.getSymbolCount()]);\n      stats.push([\"Types\", program.getTypeCount()]);\n      stats.push([\"Instantiations\", program.getInstantiationCount()]);\n    } else if (fileCount != null) {\n      stats.push([\"Files\", fileCount]);\n    }\n    const programTime = ts.performance.getDuration(\"Program\");\n    const bindTime = ts.performance.getDuration(\"Bind\");\n    const checkTime = ts.performance.getDuration(\"Check\");\n    const emitTime = ts.performance.getDuration(\"Emit\");\n    stats.push([\"Parse time\", programTime]);\n    stats.push([\"Bind time\", bindTime]);\n    stats.push([\"Check time\", checkTime]);\n    stats.push([\"Emit time\", emitTime]);\n    stats.push(\n      [\"Total TS time\", programTime + bindTime + checkTime + emitTime],\n    );\n  }\n\n  function performanceEnd() {\n    const duration = Date.now() - statsStart;\n    stats.push([\"Compile time\", duration]);\n    return stats;\n  }\n\n  /**\n   * @typedef {object} Request\n   * @property {Record<string, any>} config\n   * @property {boolean} debug\n   * @property {string[]} rootNames\n   */\n\n  /** The API that is called by Rust when executing a request.\n   * @param {Request} request\n   */\n  function exec({ config, debug: debugFlag, rootNames }) {\n    setLogDebug(debugFlag, \"TS\");\n    performanceStart();\n    debug(\">>> exec start\", { rootNames });\n    debug(config);\n\n    const { options, errors: configFileParsingDiagnostics } = ts\n      .convertCompilerOptionsFromJson(config, \"\");\n    // The `allowNonTsExtensions` is a \"hidden\" compiler option used in VSCode\n    // which is not allowed to be passed in JSON, we need it to allow special\n    // URLs which Deno supports. So we need to either ignore the diagnostic, or\n    // inject it ourselves.\n    Object.assign(options, { allowNonTsExtensions: true });\n    const program = ts.createIncrementalProgram({\n      rootNames,\n      options,\n      host,\n      configFileParsingDiagnostics,\n    });\n\n    const { diagnostics: emitDiagnostics } = program.emit();\n\n    const diagnostics = [\n      ...program.getConfigFileParsingDiagnostics(),\n      ...program.getSyntacticDiagnostics(),\n      ...program.getOptionsDiagnostics(),\n      ...program.getGlobalDiagnostics(),\n      ...program.getSemanticDiagnostics(),\n      ...emitDiagnostics,\n    ].filter(({ code }) => !IGNORED_DIAGNOSTICS.includes(code));\n    performanceProgram({ program });\n\n    core.jsonOpSync(\"op_respond\", {\n      diagnostics: fromTypeScriptDiagnostic(diagnostics),\n      stats: performanceEnd(),\n    });\n    debug(\"<<< exec stop\");\n  }\n\n  /**\n   * @param {number} id \n   * @param {any} data \n   */\n  function respond(id, data = null) {\n    core.jsonOpSync(\"op_respond\", { id, data });\n  }\n\n  /**\n   * @param {LanguageServerRequest} request \n   */\n  function serverRequest({ id, ...request }) {\n    debug(`serverRequest()`, { id, ...request });\n    switch (request.method) {\n      case \"configure\": {\n        const { options, errors } = ts\n          .convertCompilerOptionsFromJson(request.compilerOptions, \"\");\n        Object.assign(options, { allowNonTsExtensions: true });\n        if (errors.length) {\n          debug(ts.formatDiagnostics(errors, host));\n        }\n        compilationSettings = options;\n        return respond(id, true);\n      }\n      case \"getAsset\": {\n        const sourceFile = host.getSourceFile(\n          request.specifier,\n          ts.ScriptTarget.ESNext,\n        );\n        return respond(id, sourceFile && sourceFile.text);\n      }\n      case \"getDiagnostics\": {\n        try {\n          /** @type {Record<string, any[]>} */\n          const diagnosticMap = {};\n          for (const specifier of request.specifiers) {\n            diagnosticMap[specifier] = fromTypeScriptDiagnostic([\n              ...languageService.getSemanticDiagnostics(specifier),\n              ...languageService.getSuggestionDiagnostics(specifier),\n              ...languageService.getSyntacticDiagnostics(specifier),\n            ].filter(({ code }) => !IGNORED_DIAGNOSTICS.includes(code)));\n          }\n          return respond(id, diagnosticMap);\n        } catch (e) {\n          if (\"stack\" in e) {\n            error(e.stack);\n          } else {\n            error(e);\n          }\n          return respond(id, {});\n        }\n      }\n      case \"getQuickInfo\": {\n        return respond(\n          id,\n          languageService.getQuickInfoAtPosition(\n            request.specifier,\n            request.position,\n          ),\n        );\n      }\n      case \"getCompletions\": {\n        return respond(\n          id,\n          languageService.getCompletionsAtPosition(\n            request.specifier,\n            request.position,\n            request.preferences,\n          ),\n        );\n      }\n      case \"getDocumentHighlights\": {\n        return respond(\n          id,\n          languageService.getDocumentHighlights(\n            request.specifier,\n            request.position,\n            request.filesToSearch,\n          ),\n        );\n      }\n      case \"getReferences\": {\n        return respond(\n          id,\n          languageService.getReferencesAtPosition(\n            request.specifier,\n            request.position,\n          ),\n        );\n      }\n      case \"getDefinition\": {\n        return respond(\n          id,\n          languageService.getDefinitionAndBoundSpan(\n            request.specifier,\n            request.position,\n          ),\n        );\n      }\n      case \"getImplementation\": {\n        return respond(\n          id,\n          languageService.getImplementationAtPosition(\n            request.specifier,\n            request.position,\n          ),\n        );\n      }\n      case \"findRenameLocations\": {\n        return respond(\n          id,\n          languageService.findRenameLocations(\n            request.specifier,\n            request.position,\n            request.findInStrings,\n            request.findInComments,\n            request.providePrefixAndSuffixTextForRename,\n          ),\n        );\n      }\n      default:\n        throw new TypeError(\n          // @ts-ignore exhausted case statement sets type to never\n          `Invalid request method for request: \"${request.method}\" (${id})`,\n        );\n    }\n  }\n\n  /** @param {{ debug: boolean; }} init */\n  function serverInit({ debug: debugFlag }) {\n    if (hasStarted) {\n      throw new Error(\"The language server has already been initialized.\");\n    }\n    hasStarted = true;\n    languageService = ts.createLanguageService(host);\n    core.ops();\n    setLogDebug(debugFlag, \"TSLS\");\n    debug(\"serverInit()\");\n  }\n\n  let hasStarted = false;\n\n  /** Startup the runtime environment, setting various flags.\n   * @param {{ debugFlag?: boolean; legacyFlag?: boolean; }} msg\n   */\n  function startup({ debugFlag = false }) {\n    if (hasStarted) {\n      throw new Error(\"The compiler runtime already started.\");\n    }\n    hasStarted = true;\n    core.ops();\n    setLogDebug(!!debugFlag, \"TS\");\n  }\n\n  // Setup the compiler runtime during the build process.\n  core.ops();\n  core.registerErrorClass(\"Error\", Error);\n\n  // A build time only op that provides some setup information that is used to\n  // ensure the snapshot is setup properly.\n  /** @type {{ buildSpecifier: string; libs: string[] }} */\n  const { buildSpecifier, libs } = core.jsonOpSync(\"op_build_info\", {});\n  for (const lib of libs) {\n    const specifier = `lib.${lib}.d.ts`;\n    // we are using internal APIs here to \"inject\" our custom libraries into\n    // tsc, so things like `\"lib\": [ \"deno.ns\" ]` are supported.\n    if (!ts.libs.includes(lib)) {\n      ts.libs.push(lib);\n      ts.libMap.set(lib, `lib.${lib}.d.ts`);\n    }\n    // we are caching in memory common type libraries that will be re-used by\n    // tsc on when the snapshot is restored\n    assert(\n      host.getSourceFile(`${ASSETS}${specifier}`, ts.ScriptTarget.ESNext),\n    );\n  }\n  // this helps ensure as much as possible is in memory that is re-usable\n  // before the snapshotting is done, which helps unsure fast \"startup\" for\n  // subsequent uses of tsc in Deno.\n  const TS_SNAPSHOT_PROGRAM = ts.createProgram({\n    rootNames: [buildSpecifier],\n    options: SNAPSHOT_COMPILE_OPTIONS,\n    host,\n  });\n  ts.getPreEmitDiagnostics(TS_SNAPSHOT_PROGRAM);\n\n  // exposes the two functions that are called by `tsc::exec()` when type\n  // checking TypeScript.\n  globalThis.startup = startup;\n  globalThis.exec = exec;\n\n  // exposes the functions that are called when the compiler is used as a\n  // language service.\n  globalThis.serverInit = serverInit;\n  globalThis.serverRequest = serverRequest;\n})(this);\n"
-  }
-}
diff --git a/cli/tests/testdata/lsp/did_open_params_semantic_tokens.json b/cli/tests/testdata/lsp/did_open_params_semantic_tokens.json
deleted file mode 100644
index 5cf48ae05188a3..00000000000000
--- a/cli/tests/testdata/lsp/did_open_params_semantic_tokens.json
+++ /dev/null
@@ -1,8 +0,0 @@
-{
-  "textDocument": {
-    "uri": "file:///a/file.ts",
-    "languageId": "typescript",
-    "version": 1,
-    "text": "enum Values { value1, value2 }\n\nasync function baz(s: string): Promise<string> {\n  const r = s.slice(0);\n  return r;\n}\n\ninterface IFoo {\n  readonly x: number;\n  foo(): boolean;\n}\n\nclass Bar implements IFoo {\n  constructor(public readonly x: number) { }\n  foo() { return true; }\n  static staticBar = new Bar(0);\n  private static getStaticBar() { return Bar.staticBar; }\n}\n"
-  }
-}
diff --git a/cli/tests/testdata/lsp/did_open_params_test_code_lens.json b/cli/tests/testdata/lsp/did_open_params_test_code_lens.json
deleted file mode 100644
index dcb9e11f30af42..00000000000000
--- a/cli/tests/testdata/lsp/did_open_params_test_code_lens.json
+++ /dev/null
@@ -1,8 +0,0 @@
-{
-  "textDocument": {
-    "uri": "file:///a/file.ts",
-    "languageId": "typescript",
-    "version": 1,
-    "text": "const { test } = Deno;\nconst { test: test2 } = Deno;\nconst test3 = Deno.test;\n\nDeno.test(\"test a\", () => {});\nDeno.test({\n  name: \"test b\",\n  fn() {},\n});\ntest({\n  name: \"test c\",\n  fn() {},\n});\ntest(\"test d\", () => {});\ntest2({\n  name: \"test e\",\n  fn() {},\n});\ntest2(\"test f\", () => {});\ntest3({\n  name: \"test g\",\n  fn() {},\n});\ntest3(\"test h\", () => {});\n"
-  }
-}
diff --git a/cli/tests/testdata/lsp/did_open_params_tls_cert.json b/cli/tests/testdata/lsp/did_open_params_tls_cert.json
deleted file mode 100644
index 2942bfcbeb44ee..00000000000000
--- a/cli/tests/testdata/lsp/did_open_params_tls_cert.json
+++ /dev/null
@@ -1,8 +0,0 @@
-{
-  "textDocument": {
-    "uri": "file:///a/file.ts",
-    "languageId": "typescript",
-    "version": 1,
-    "text": "import * as a from \"https://localhost:5545/xTypeScriptTypes.js\";\n// @deno-types=\"https://localhost:5545/type_definitions/foo.d.ts\"\nimport * as b from \"https://localhost:5545/type_definitions/foo.js\";\nimport * as c from \"https://localhost:5545/subdir/type_reference.js\";\nimport * as d from \"https://localhost:5545/subdir/mod1.ts\";\nimport * as e from \"data:application/typescript;base64,ZXhwb3J0IGNvbnN0IGEgPSAiYSI7CgpleHBvcnQgZW51bSBBIHsKICBBLAogIEIsCiAgQywKfQo=\";\nimport * as f from \"./file_01.ts\";\nimport * as g from \"http://localhost:4545/x/a/mod.ts\";\n\nconsole.log(a, b, c, d, e, f, g);\n"
-  }
-}
diff --git a/cli/tests/testdata/lsp/document_symbol_response.json b/cli/tests/testdata/lsp/document_symbol_response.json
deleted file mode 100644
index 90dd76411ff80f..00000000000000
--- a/cli/tests/testdata/lsp/document_symbol_response.json
+++ /dev/null
@@ -1,371 +0,0 @@
-[
-  {
-    "name": "bar",
-    "kind": 13,
-    "range": {
-      "start": {
-        "line": 17,
-        "character": 4
-      },
-      "end": {
-        "line": 17,
-        "character": 26
-      }
-    },
-    "selectionRange": {
-      "start": {
-        "line": 17,
-        "character": 4
-      },
-      "end": {
-        "line": 17,
-        "character": 7
-      }
-    }
-  },
-  {
-    "name": "Bar",
-    "kind": 5,
-    "range": {
-      "start": {
-        "line": 4,
-        "character": 0
-      },
-      "end": {
-        "line": 13,
-        "character": 1
-      }
-    },
-    "selectionRange": {
-      "start": {
-        "line": 4,
-        "character": 6
-      },
-      "end": {
-        "line": 4,
-        "character": 9
-      }
-    },
-    "children": [
-      {
-        "name": "constructor",
-        "kind": 9,
-        "range": {
-          "start": {
-            "line": 5,
-            "character": 2
-          },
-          "end": {
-            "line": 5,
-            "character": 35
-          }
-        },
-        "selectionRange": {
-          "start": {
-            "line": 5,
-            "character": 2
-          },
-          "end": {
-            "line": 5,
-            "character": 35
-          }
-        }
-      },
-      {
-        "name": "baz",
-        "kind": 6,
-        "tags": [
-          1
-        ],
-        "range": {
-          "start": {
-            "line": 8,
-            "character": 2
-          },
-          "end": {
-            "line": 8,
-            "character": 25
-          }
-        },
-        "selectionRange": {
-          "start": {
-            "line": 8,
-            "character": 2
-          },
-          "end": {
-            "line": 8,
-            "character": 5
-          }
-        }
-      },
-      {
-        "name": "foo",
-        "kind": 6,
-        "range": {
-          "start": {
-            "line": 6,
-            "character": 2
-          },
-          "end": {
-            "line": 6,
-            "character": 24
-          }
-        },
-        "selectionRange": {
-          "start": {
-            "line": 6,
-            "character": 2
-          },
-          "end": {
-            "line": 6,
-            "character": 5
-          }
-        }
-      },
-      {
-        "name": "getStaticBar",
-        "kind": 6,
-        "range": {
-          "start": {
-            "line": 12,
-            "character": 2
-          },
-          "end": {
-            "line": 12,
-            "character": 57
-          }
-        },
-        "selectionRange": {
-          "start": {
-            "line": 12,
-            "character": 17
-          },
-          "end": {
-            "line": 12,
-            "character": 29
-          }
-        }
-      },
-      {
-        "name": "staticBar",
-        "kind": 8,
-        "range": {
-          "start": {
-            "line": 11,
-            "character": 2
-          },
-          "end": {
-            "line": 11,
-            "character": 32
-          }
-        },
-        "selectionRange": {
-          "start": {
-            "line": 11,
-            "character": 9
-          },
-          "end": {
-            "line": 11,
-            "character": 18
-          }
-        }
-      },
-      {
-        "name": "(get) value",
-        "kind": 8,
-        "range": {
-          "start": {
-            "line": 9,
-            "character": 2
-          },
-          "end": {
-            "line": 9,
-            "character": 35
-          }
-        },
-        "selectionRange": {
-          "start": {
-            "line": 9,
-            "character": 6
-          },
-          "end": {
-            "line": 9,
-            "character": 11
-          }
-        }
-      },
-      {
-        "name": "(set) value",
-        "kind": 8,
-        "range": {
-          "start": {
-            "line": 10,
-            "character": 2
-          },
-          "end": {
-            "line": 10,
-            "character": 42
-          }
-        },
-        "selectionRange": {
-          "start": {
-            "line": 10,
-            "character": 6
-          },
-          "end": {
-            "line": 10,
-            "character": 11
-          }
-        }
-      },
-      {
-        "name": "x",
-        "kind": 8,
-        "range": {
-          "start": {
-            "line": 5,
-            "character": 14
-          },
-          "end": {
-            "line": 5,
-            "character": 30
-          }
-        },
-        "selectionRange": {
-          "start": {
-            "line": 5,
-            "character": 21
-          },
-          "end": {
-            "line": 5,
-            "character": 22
-          }
-        }
-      }
-    ]
-  },
-  {
-    "name": "IFoo",
-    "kind": 11,
-    "range": {
-      "start": {
-        "line": 0,
-        "character": 0
-      },
-      "end": {
-        "line": 2,
-        "character": 1
-      }
-    },
-    "selectionRange": {
-      "start": {
-        "line": 0,
-        "character": 10
-      },
-      "end": {
-        "line": 0,
-        "character": 14
-      }
-    },
-    "children": [
-      {
-        "name": "foo",
-        "kind": 6,
-        "range": {
-          "start": {
-            "line": 1,
-            "character": 2
-          },
-          "end": {
-            "line": 1,
-            "character": 17
-          }
-        },
-        "selectionRange": {
-          "start": {
-            "line": 1,
-            "character": 2
-          },
-          "end": {
-            "line": 1,
-            "character": 5
-          }
-        }
-      }
-    ]
-  },
-  {
-    "name": "Values",
-    "kind": 10,
-    "range": {
-      "start": {
-        "line": 15,
-        "character": 0
-      },
-      "end": {
-        "line": 15,
-        "character": 30
-      }
-    },
-    "selectionRange": {
-      "start": {
-        "line": 15,
-        "character": 5
-      },
-      "end": {
-        "line": 15,
-        "character": 11
-      }
-    },
-    "children": [
-      {
-        "name": "value1",
-        "kind": 22,
-        "range": {
-          "start": {
-            "line": 15,
-            "character": 14
-          },
-          "end": {
-            "line": 15,
-            "character": 20
-          }
-        },
-        "selectionRange": {
-          "start": {
-            "line": 15,
-            "character": 14
-          },
-          "end": {
-            "line": 15,
-            "character": 20
-          }
-        }
-      },
-      {
-        "name": "value2",
-        "kind": 22,
-        "range": {
-          "start": {
-            "line": 15,
-            "character": 22
-          },
-          "end": {
-            "line": 15,
-            "character": 28
-          }
-        },
-        "selectionRange": {
-          "start": {
-            "line": 15,
-            "character": 22
-          },
-          "end": {
-            "line": 15,
-            "character": 28
-          }
-        }
-      }
-    ]
-  }
-]
diff --git a/cli/tests/testdata/lsp/formatting_mbc_response.json b/cli/tests/testdata/lsp/formatting_mbc_response.json
deleted file mode 100644
index 1c0b9f8e890637..00000000000000
--- a/cli/tests/testdata/lsp/formatting_mbc_response.json
+++ /dev/null
@@ -1,54 +0,0 @@
-[
-  {
-    "range": {
-      "start": {
-        "line": 0,
-        "character": 12
-      },
-      "end": {
-        "line": 0,
-        "character": 13
-      }
-    },
-    "newText": "\""
-  },
-  {
-    "range": {
-      "start": {
-        "line": 0,
-        "character": 21
-      },
-      "end": {
-        "line": 0,
-        "character": 22
-      }
-    },
-    "newText": "\";"
-  },
-  {
-    "range": {
-      "start": {
-        "line": 1,
-        "character": 12
-      },
-      "end": {
-        "line": 1,
-        "character": 13
-      }
-    },
-    "newText": "\""
-  },
-  {
-    "range": {
-      "start": {
-        "line": 1,
-        "character": 23
-      },
-      "end": {
-        "line": 1,
-        "character": 25
-      }
-    },
-    "newText": "\");"
-  }
-]
diff --git a/cli/tests/testdata/lsp/import-map-completions.json b/cli/tests/testdata/lsp/import-map-completions.json
deleted file mode 100644
index f2275222af61d1..00000000000000
--- a/cli/tests/testdata/lsp/import-map-completions.json
+++ /dev/null
@@ -1,7 +0,0 @@
-{
-  "imports": {
-    "/~/": "./lib/",
-    "fs": "https://example.com/fs/index.js",
-    "std/": "https://example.com/std@0.123.0/"
-  }
-}
diff --git a/cli/tests/testdata/lsp/incoming_calls_params.json b/cli/tests/testdata/lsp/incoming_calls_params.json
deleted file mode 100644
index 6b38d26ee59179..00000000000000
--- a/cli/tests/testdata/lsp/incoming_calls_params.json
+++ /dev/null
@@ -1,28 +0,0 @@
-{
-  "item": {
-    "name": "baz",
-    "kind": 6,
-    "detail": "Bar",
-    "uri": "file:///a/file.ts",
-    "range": {
-      "start": {
-        "line": 5,
-        "character": 2
-      },
-      "end": {
-        "line": 7,
-        "character": 3
-      }
-    },
-    "selectionRange": {
-      "start": {
-        "line": 5,
-        "character": 2
-      },
-      "end": {
-        "line": 5,
-        "character": 5
-      }
-    }
-  }
-}
diff --git a/cli/tests/testdata/lsp/incoming_calls_response.json b/cli/tests/testdata/lsp/incoming_calls_response.json
deleted file mode 100644
index 231919a8c81996..00000000000000
--- a/cli/tests/testdata/lsp/incoming_calls_response.json
+++ /dev/null
@@ -1,42 +0,0 @@
-[
-  {
-    "from": {
-      "name": "main",
-      "kind": 12,
-      "detail": "",
-      "uri": "file:///a/file.ts",
-      "range": {
-        "start": {
-          "line": 10,
-          "character": 0
-        },
-        "end": {
-          "line": 13,
-          "character": 1
-        }
-      },
-      "selectionRange": {
-        "start": {
-          "line": 10,
-          "character": 9
-        },
-        "end": {
-          "line": 10,
-          "character": 13
-        }
-      }
-    },
-    "fromRanges": [
-      {
-        "start": {
-          "line": 12,
-          "character": 6
-        },
-        "end": {
-          "line": 12,
-          "character": 9
-        }
-      }
-    ]
-  }
-]
diff --git a/cli/tests/testdata/lsp/initialize_params.json b/cli/tests/testdata/lsp/initialize_params.json
deleted file mode 100644
index 68735b06dee000..00000000000000
--- a/cli/tests/testdata/lsp/initialize_params.json
+++ /dev/null
@@ -1,82 +0,0 @@
-{
-  "processId": 0,
-  "clientInfo": {
-    "name": "test-harness",
-    "version": "1.0.0"
-  },
-  "rootUri": null,
-  "initializationOptions": {
-    "enable": true,
-    "cache": null,
-    "certificateStores": null,
-    "codeLens": {
-      "implementations": true,
-      "references": true,
-      "test": true
-    },
-    "config": null,
-    "importMap": null,
-    "lint": true,
-    "suggest": {
-      "autoImports": true,
-      "completeFunctionCalls": false,
-      "names": true,
-      "paths": true,
-      "imports": {
-        "hosts": {}
-      }
-    },
-    "testing": {
-      "args": [
-        "--allow-all"
-      ],
-      "enable": true
-    },
-    "tlsCertificate": null,
-    "unsafelyIgnoreCertificateErrors": null,
-    "unstable": false
-  },
-  "capabilities": {
-    "textDocument": {
-      "codeAction": {
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-        "isPreferredSupport": true,
-        "dataSupport": true,
-        "disabledSupport": true,
-        "resolveSupport": {
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-            "edit"
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-        "dynamicRegistration": true,
-        "willSave": true,
-        "willSaveWaitUntil": true,
-        "didSave": true
-      }
-    },
-    "workspace": {
-      "configuration": true,
-      "workspaceFolders": true
-    },
-    "experimental": {
-      "testingApi": true
-    }
-  }
-}
diff --git a/cli/tests/testdata/lsp/initialize_params_bad_config_option.json b/cli/tests/testdata/lsp/initialize_params_bad_config_option.json
deleted file mode 100644
index 053cb70f39bb55..00000000000000
--- a/cli/tests/testdata/lsp/initialize_params_bad_config_option.json
+++ /dev/null
@@ -1,65 +0,0 @@
-{
-  "processId": 0,
-  "clientInfo": {
-    "name": "test-harness",
-    "version": "1.0.0"
-  },
-  "rootUri": null,
-  "initializationOptions": {
-    "enable": true,
-    "cache": null,
-    "codeLens": {
-      "implementations": true,
-      "references": true,
-      "test": true
-    },
-    "config": "bad_tsconfig.json",
-    "importMap": null,
-    "lint": true,
-    "suggest": {
-      "autoImports": true,
-      "completeFunctionCalls": false,
-      "names": true,
-      "paths": true,
-      "imports": {
-        "hosts": {}
-      }
-    },
-    "unstable": false
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-  "capabilities": {
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-        "isPreferredSupport": true,
-        "dataSupport": true,
-        "disabledSupport": true,
-        "resolveSupport": {
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-      "foldingRange": {
-        "lineFoldingOnly": true
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-      "synchronization": {
-        "dynamicRegistration": true,
-        "willSave": true,
-        "willSaveWaitUntil": true,
-        "didSave": true
-      }
-    },
-    "workspace": {
-      "configuration": true,
-      "workspaceFolders": true
-    }
-  }
-}
diff --git a/cli/tests/testdata/lsp/initialize_params_ca_no_disabled.json b/cli/tests/testdata/lsp/initialize_params_ca_no_disabled.json
deleted file mode 100644
index 3df87aded3da9d..00000000000000
--- a/cli/tests/testdata/lsp/initialize_params_ca_no_disabled.json
+++ /dev/null
@@ -1,64 +0,0 @@
-{
-  "processId": 0,
-  "clientInfo": {
-    "name": "test-harness",
-    "version": "1.0.0"
-  },
-  "rootUri": null,
-  "initializationOptions": {
-    "enable": true,
-    "cache": null,
-    "codeLens": {
-      "implementations": true,
-      "references": true,
-      "test": true
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-    "config": "",
-    "importMap": null,
-    "lint": true,
-    "suggest": {
-      "autoImports": true,
-      "completeFunctionCalls": false,
-      "names": true,
-      "paths": true,
-      "imports": {
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-      }
-    },
-    "unstable": false
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-  "capabilities": {
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-        "dataSupport": true,
-        "resolveSupport": {
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-      "foldingRange": {
-        "lineFoldingOnly": true
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-      "synchronization": {
-        "dynamicRegistration": true,
-        "willSave": true,
-        "willSaveWaitUntil": true,
-        "didSave": true
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-    },
-    "workspace": {
-      "configuration": true,
-      "workspaceFolders": true
-    }
-  }
-}
diff --git a/cli/tests/testdata/lsp/initialize_params_code_lens_test.json b/cli/tests/testdata/lsp/initialize_params_code_lens_test.json
deleted file mode 100644
index bdd01bfca7902e..00000000000000
--- a/cli/tests/testdata/lsp/initialize_params_code_lens_test.json
+++ /dev/null
@@ -1,59 +0,0 @@
-{
-  "processId": 0,
-  "clientInfo": {
-    "name": "test-harness",
-    "version": "1.0.0"
-  },
-  "rootUri": null,
-  "initializationOptions": {
-    "enable": true,
-    "cache": null,
-    "importMap": null,
-    "lint": true,
-    "suggest": {
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-      "completeFunctionCalls": false,
-      "names": true,
-      "paths": true,
-      "imports": {
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-    "unstable": false
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-  "capabilities": {
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-        "resolveSupport": {
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-      "foldingRange": {
-        "lineFoldingOnly": true
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-        "dynamicRegistration": true,
-        "willSave": true,
-        "willSaveWaitUntil": true,
-        "didSave": true
-      }
-    },
-    "workspace": {
-      "configuration": true,
-      "workspaceFolders": true
-    }
-  }
-}
diff --git a/cli/tests/testdata/lsp/initialize_params_code_lens_test_disabled.json b/cli/tests/testdata/lsp/initialize_params_code_lens_test_disabled.json
deleted file mode 100644
index 1d18934ae86d74..00000000000000
--- a/cli/tests/testdata/lsp/initialize_params_code_lens_test_disabled.json
+++ /dev/null
@@ -1,64 +0,0 @@
-{
-  "processId": 0,
-  "clientInfo": {
-    "name": "test-harness",
-    "version": "1.0.0"
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-  "rootUri": null,
-  "initializationOptions": {
-    "enable": true,
-    "cache": null,
-    "codeLens": {
-      "implementations": true,
-      "references": true,
-      "test": false
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-    "importMap": null,
-    "lint": true,
-    "suggest": {
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-      "completeFunctionCalls": false,
-      "names": true,
-      "paths": true,
-      "imports": {
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-        "didSave": true
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-    "workspace": {
-      "configuration": true,
-      "workspaceFolders": true
-    }
-  }
-}
diff --git a/cli/tests/testdata/lsp/initialize_params_did_config_change.json b/cli/tests/testdata/lsp/initialize_params_did_config_change.json
deleted file mode 100644
index 870ad6e0f1a239..00000000000000
--- a/cli/tests/testdata/lsp/initialize_params_did_config_change.json
+++ /dev/null
@@ -1,65 +0,0 @@
-{
-  "processId": 0,
-  "clientInfo": {
-    "name": "test-harness",
-    "version": "1.0.0"
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-  "rootUri": null,
-  "initializationOptions": {
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-    "codeLens": {
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-      "references": true
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-    "lint": true,
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-      "autoImports": true,
-      "completeFunctionCalls": false,
-      "names": true,
-      "paths": true,
-      "imports": {
-        "hosts": {
-          "http://localhost:4545/": false
-        }
-      }
-    },
-    "unstable": false
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-  "capabilities": {
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-        "isPreferredSupport": true,
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-        "disabledSupport": true,
-        "resolveSupport": {
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-        "didSave": true
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-    },
-    "workspace": {
-      "configuration": true,
-      "workspaceFolders": true
-    }
-  }
-}
diff --git a/cli/tests/testdata/lsp/initialize_params_disabled.json b/cli/tests/testdata/lsp/initialize_params_disabled.json
deleted file mode 100644
index 879b1181c8731f..00000000000000
--- a/cli/tests/testdata/lsp/initialize_params_disabled.json
+++ /dev/null
@@ -1,63 +0,0 @@
-{
-  "processId": 0,
-  "clientInfo": {
-    "name": "test-harness",
-    "version": "1.0.0"
-  },
-  "rootUri": null,
-  "initializationOptions": {
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-    "cache": null,
-    "codeLens": {
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-      "references": true
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-    "lint": true,
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-      "completeFunctionCalls": false,
-      "names": true,
-      "paths": true,
-      "imports": {
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-        "willSave": true,
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-        "didSave": true
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-    "workspace": {
-      "configuration": true,
-      "workspaceFolders": true
-    }
-  }
-}
diff --git a/cli/tests/testdata/lsp/initialize_params_hints.json b/cli/tests/testdata/lsp/initialize_params_hints.json
deleted file mode 100644
index 1bab6e86d8b518..00000000000000
--- a/cli/tests/testdata/lsp/initialize_params_hints.json
+++ /dev/null
@@ -1,102 +0,0 @@
-{
-  "processId": 0,
-  "clientInfo": {
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-    "version": "1.0.0"
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-  "rootUri": null,
-  "initializationOptions": {
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-    "cache": null,
-    "certificateStores": null,
-    "codeLens": {
-      "implementations": true,
-      "references": true,
-      "test": true
-    },
-    "config": null,
-    "importMap": null,
-    "inlayHints": {
-      "parameterNames": {
-        "enabled": "all"
-      },
-      "parameterTypes": {
-        "enabled": true
-      },
-      "variableTypes": {
-        "enabled": true
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-      "propertyDeclarationTypes": {
-        "enabled": true
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-      "functionLikeReturnTypes": {
-        "enabled": true
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-      "enumMemberValues": {
-        "enabled": true
-      }
-    },
-    "lint": true,
-    "suggest": {
-      "autoImports": true,
-      "completeFunctionCalls": false,
-      "names": true,
-      "paths": true,
-      "imports": {
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-      }
-    },
-    "testing": {
-      "args": [
-        "--allow-all"
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-      "enable": true
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-    "tlsCertificate": null,
-    "unsafelyIgnoreCertificateErrors": null,
-    "unstable": false
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-  "capabilities": {
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-      "completion": {
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-      "synchronization": {
-        "dynamicRegistration": true,
-        "willSave": true,
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-    },
-    "workspace": {
-      "configuration": true,
-      "workspaceFolders": true
-    },
-    "experimental": {
-      "testingApi": true
-    }
-  }
-}
diff --git a/cli/tests/testdata/lsp/initialize_params_import_map.json b/cli/tests/testdata/lsp/initialize_params_import_map.json
deleted file mode 100644
index 2ba7d28b05a457..00000000000000
--- a/cli/tests/testdata/lsp/initialize_params_import_map.json
+++ /dev/null
@@ -1,62 +0,0 @@
-{
-  "processId": 0,
-  "clientInfo": {
-    "name": "test-harness",
-    "version": "1.0.0"
-  },
-  "rootUri": null,
-  "initializationOptions": {
-    "enable": true,
-    "codeLens": {
-      "implementations": true,
-      "references": true
-    },
-    "importMap": "data:application/json;utf8,{\"imports\": { \"example\": \"https://deno.land/x/example/mod.ts\" }}",
-    "lint": true,
-    "suggest": {
-      "autoImports": true,
-      "completeFunctionCalls": false,
-      "names": true,
-      "paths": true,
-      "imports": {
-        "hosts": {
-          "http://localhost:4545/": false
-        }
-      }
-    },
-    "unstable": false
-  },
-  "capabilities": {
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-              "quickfix"
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-        "dataSupport": true,
-        "resolveSupport": {
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-        "dynamicRegistration": true,
-        "willSave": true,
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-        "didSave": true
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-    "workspace": {
-      "configuration": true,
-      "workspaceFolders": true
-    }
-  }
-}
diff --git a/cli/tests/testdata/lsp/initialize_params_no_snippet.json b/cli/tests/testdata/lsp/initialize_params_no_snippet.json
deleted file mode 100644
index b076f3b1759802..00000000000000
--- a/cli/tests/testdata/lsp/initialize_params_no_snippet.json
+++ /dev/null
@@ -1,77 +0,0 @@
-{
-  "processId": 0,
-  "clientInfo": {
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-    "version": "1.0.0"
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-  "rootUri": null,
-  "initializationOptions": {
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-    "certificateStores": null,
-    "codeLens": {
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-      "references": true,
-      "test": true
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-    "config": null,
-    "importMap": null,
-    "lint": true,
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-      "completeFunctionCalls": false,
-      "names": true,
-      "paths": true,
-      "imports": {
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-    "testing": {
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-        "didSave": true
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-    "workspace": {
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-      "workspaceFolders": true
-    },
-    "experimental": {
-      "testingApi": true
-    }
-  }
-}
diff --git a/cli/tests/testdata/lsp/initialize_params_registry.json b/cli/tests/testdata/lsp/initialize_params_registry.json
deleted file mode 100644
index 286f6085f1e4f3..00000000000000
--- a/cli/tests/testdata/lsp/initialize_params_registry.json
+++ /dev/null
@@ -1,67 +0,0 @@
-{
-  "processId": 0,
-  "clientInfo": {
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-  "initializationOptions": {
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-    "codeLens": {
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-    "importMap": null,
-    "lint": true,
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-      "names": true,
-      "paths": true,
-      "imports": {
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-        "didSave": true
-      }
-    },
-    "workspace": {
-      "configuration": true,
-      "workspaceFolders": true
-    }
-  }
-}
diff --git a/cli/tests/testdata/lsp/initialize_params_tls_cert.json b/cli/tests/testdata/lsp/initialize_params_tls_cert.json
deleted file mode 100644
index e231bf25faf766..00000000000000
--- a/cli/tests/testdata/lsp/initialize_params_tls_cert.json
+++ /dev/null
@@ -1,71 +0,0 @@
-{
-  "processId": 0,
-  "clientInfo": {
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-    "version": "1.0.0"
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-  "initializationOptions": {
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-    "cache": null,
-    "certificateStores": null,
-    "codeLens": {
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-    "importMap": null,
-    "lint": true,
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-      "completeFunctionCalls": false,
-      "names": true,
-      "paths": true,
-      "imports": {
-        "hosts": {
-          "https://localhost:5545": true,
-          "http://localhost:4545": true
-        }
-      }
-    },
-    "tlsCertificate": "tls/RootCA.pem",
-    "unsafelyIgnoreCertificateErrors": null,
-    "unstable": false
-  },
-  "capabilities": {
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-        "didSave": true
-      }
-    },
-    "workspace": {
-      "configuration": true,
-      "workspaceFolders": true
-    }
-  }
-}
diff --git a/cli/tests/testdata/lsp/initialize_params_unstable.json b/cli/tests/testdata/lsp/initialize_params_unstable.json
deleted file mode 100644
index 104db16f24b946..00000000000000
--- a/cli/tests/testdata/lsp/initialize_params_unstable.json
+++ /dev/null
@@ -1,63 +0,0 @@
-{
-  "processId": 0,
-  "clientInfo": {
-    "name": "test-harness",
-    "version": "1.0.0"
-  },
-  "rootUri": null,
-  "initializationOptions": {
-    "enable": true,
-    "cache": null,
-    "codeLens": {
-      "implementations": true,
-      "references": true
-    },
-    "importMap": null,
-    "lint": true,
-    "suggest": {
-      "autoImports": true,
-      "completeFunctionCalls": false,
-      "names": true,
-      "paths": true,
-      "imports": {
-        "hosts": {}
-      }
-    },
-    "unstable": true
-  },
-  "capabilities": {
-    "textDocument": {
-      "codeAction": {
-        "codeActionLiteralSupport": {
-          "codeActionKind": {
-            "valueSet": [
-              "quickfix",
-              "refactor"
-            ]
-          }
-        },
-        "isPreferredSupport": true,
-        "dataSupport": true,
-        "disabledSupport": true,
-        "resolveSupport": {
-          "properties": [
-            "edit"
-          ]
-        }
-      },
-      "foldingRange": {
-        "lineFoldingOnly": true
-      },
-      "synchronization": {
-        "dynamicRegistration": true,
-        "willSave": true,
-        "willSaveWaitUntil": true,
-        "didSave": true
-      }
-    },
-    "workspace": {
-      "configuration": true,
-      "workspaceFolders": true
-    }
-  }
-}
diff --git a/cli/tests/testdata/lsp/initialize_params_workspace_enable_paths.json b/cli/tests/testdata/lsp/initialize_params_workspace_enable_paths.json
deleted file mode 100644
index 87581ebd7d0480..00000000000000
--- a/cli/tests/testdata/lsp/initialize_params_workspace_enable_paths.json
+++ /dev/null
@@ -1,77 +0,0 @@
-{
-  "processId": 0,
-  "clientInfo": {
-    "name": "test-harness",
-    "version": "1.0.0"
-  },
-  "rootUri": "file:///project/",
-  "initializationOptions": {
-    "enable": false,
-    "enablePaths": [
-      "./worker"
-    ],
-    "cache": null,
-    "certificateStores": null,
-    "codeLens": {
-      "implementations": true,
-      "references": true,
-      "test": true
-    },
-    "config": "",
-    "importMap": null,
-    "lint": true,
-    "suggest": {
-      "autoImports": true,
-      "completeFunctionCalls": false,
-      "names": true,
-      "paths": true,
-      "imports": {
-        "hosts": {}
-      }
-    },
-    "tlsCertificate": null,
-    "unsafelyIgnoreCertificateErrors": null,
-    "unstable": false
-  },
-  "workspaceFolders": [
-    {
-      "uri": "file:///project/",
-      "name": "project"
-    }
-  ],
-  "capabilities": {
-    "textDocument": {
-      "codeAction": {
-        "codeActionLiteralSupport": {
-          "codeActionKind": {
-            "valueSet": [
-              "quickfix",
-              "refactor"
-            ]
-          }
-        },
-        "isPreferredSupport": true,
-        "dataSupport": true,
-        "disabledSupport": true,
-        "resolveSupport": {
-          "properties": [
-            "edit"
-          ]
-        }
-      },
-      "foldingRange": {
-        "lineFoldingOnly": true
-      },
-      "synchronization": {
-        "dynamicRegistration": true,
-        "willSave": true,
-        "willSaveWaitUntil": true,
-        "didSave": true
-      }
-    },
-    "workspace": {
-      "configuration": true,
-      "workspaceFolders": true
-    }
-  }
-}
diff --git a/cli/tests/testdata/lsp/large_file.txt b/cli/tests/testdata/lsp/large_file.txt
new file mode 100644
index 00000000000000..f1ca0481c6efeb
--- /dev/null
+++ b/cli/tests/testdata/lsp/large_file.txt
@@ -0,0 +1,676 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
+// @ts-check
+/// <reference path="./compiler.d.ts" />
+// deno-lint-ignore-file no-undef
+
+// This module is the entry point for "compiler" isolate, ie. the one
+// that is created when Deno needs to type check TypeScript, and in some
+// instances convert TypeScript to JavaScript.
+
+// Removes the `__proto__` for security reasons.  This intentionally makes
+// Deno non compliant with ECMA-262 Annex B.2.2.1
+delete Object.prototype.__proto__;
+
+((window) => {
+  /** @type {DenoCore} */
+  const core = window.Deno.core;
+
+  let logDebug = false;
+  let logSource = "JS";
+
+  function setLogDebug(debug, source) {
+    logDebug = debug;
+    if (source) {
+      logSource = source;
+    }
+  }
+
+  function debug(...args) {
+    if (logDebug) {
+      const stringifiedArgs = args.map((arg) =>
+        typeof arg === "string" ? arg : JSON.stringify(arg)
+      ).join(" ");
+      // adding a non-zero integer value to the end of the debug string causes
+      // the message to be printed to stderr instead of stdout, which is better
+      // aligned to the behaviour of debug messages
+      core.print(`DEBUG ${logSource} - ${stringifiedArgs}\n`, 1);
+    }
+  }
+
+  function error(...args) {
+    const stringifiedArgs = args.map((arg) =>
+      typeof arg === "string" || arg instanceof Error
+        ? String(arg)
+        : JSON.stringify(arg)
+    ).join(" ");
+    core.print(`ERROR ${logSource} = ${stringifiedArgs}\n`, 1);
+  }
+
+  class AssertionError extends Error {
+    constructor(msg) {
+      super(msg);
+      this.name = "AssertionError";
+    }
+  }
+
+  function assert(cond, msg = "Assertion failed.") {
+    if (!cond) {
+      throw new AssertionError(msg);
+    }
+  }
+
+  /** @type {Map<string, ts.SourceFile>} */
+  const sourceFileCache = new Map();
+
+  /** @param {ts.DiagnosticRelatedInformation} diagnostic */
+  function fromRelatedInformation({
+    start,
+    length,
+    file,
+    messageText: msgText,
+    ...ri
+  }) {
+    let messageText;
+    let messageChain;
+    if (typeof msgText === "object") {
+      messageChain = msgText;
+    } else {
+      messageText = msgText;
+    }
+    if (start !== undefined && length !== undefined && file) {
+      const startPos = file.getLineAndCharacterOfPosition(start);
+      const sourceLine = file.getFullText().split("\n")[startPos.line];
+      const fileName = file.fileName;
+      return {
+        start: startPos,
+        end: file.getLineAndCharacterOfPosition(start + length),
+        fileName,
+        messageChain,
+        messageText,
+        sourceLine,
+        ...ri,
+      };
+    } else {
+      return {
+        messageChain,
+        messageText,
+        ...ri,
+      };
+    }
+  }
+
+  /** @param {ts.Diagnostic[]} diagnostics */
+  function fromTypeScriptDiagnostic(diagnostics) {
+    return diagnostics.map(({ relatedInformation: ri, source, ...diag }) => {
+      /** @type {any} */
+      const value = fromRelatedInformation(diag);
+      value.relatedInformation = ri
+        ? ri.map(fromRelatedInformation)
+        : undefined;
+      value.source = source;
+      return value;
+    });
+  }
+
+  // Using incremental compile APIs requires that all
+  // paths must be either relative or absolute. Since
+  // analysis in Rust operates on fully resolved URLs,
+  // it makes sense to use the same scheme here.
+  const ASSETS = "asset:///";
+  const CACHE = "cache:///";
+
+  /** Diagnostics that are intentionally ignored when compiling TypeScript in
+   * Deno, as they provide misleading or incorrect information. */
+  const IGNORED_DIAGNOSTICS = [
+    // TS1208: All files must be modules when the '--isolatedModules' flag is
+    // provided.  We can ignore because we guarantee that all files are
+    // modules.
+    1208,
+    // TS1375: 'await' expressions are only allowed at the top level of a file
+    // when that file is a module, but this file has no imports or exports.
+    // Consider adding an empty 'export {}' to make this file a module.
+    1375,
+    // TS1103: 'for-await-of' statement is only allowed within an async function
+    // or async generator.
+    1103,
+    // TS2306: File 'file:///Users/rld/src/deno/subdir/amd_like.js' is
+    // not a module.
+    2306,
+    // TS2691: An import path cannot end with a '.ts' extension. Consider
+    // importing 'bad-module' instead.
+    2691,
+    // TS2792: Cannot find module. Did you mean to set the 'moduleResolution'
+    // option to 'node', or to add aliases to the 'paths' option?
+    2792,
+    // TS5009: Cannot find the common subdirectory path for the input files.
+    5009,
+    // TS5055: Cannot write file
+    // 'http://localhost:4545/subdir/mt_application_x_javascript.j4.js'
+    // because it would overwrite input file.
+    5055,
+    // TypeScript is overly opinionated that only CommonJS modules kinds can
+    // support JSON imports.  Allegedly this was fixed in
+    // Microsoft/TypeScript#26825 but that doesn't seem to be working here,
+    // so we will ignore complaints about this compiler setting.
+    5070,
+    // TS7016: Could not find a declaration file for module '...'. '...'
+    // implicitly has an 'any' type.  This is due to `allowJs` being off by
+    // default but importing of a JavaScript module.
+    7016,
+  ];
+
+  const SNAPSHOT_COMPILE_OPTIONS = {
+    esModuleInterop: true,
+    jsx: ts.JsxEmit.React,
+    module: ts.ModuleKind.ESNext,
+    noEmit: true,
+    strict: true,
+    target: ts.ScriptTarget.ESNext,
+  };
+
+  class ScriptSnapshot {
+    /** @type {string} */
+    specifier;
+    /** @type {string} */
+    version;
+    /**
+     * @param {string} specifier
+     * @param {string} version 
+     */
+    constructor(specifier, version) {
+      this.specifier = specifier;
+      this.version = version;
+    }
+    /**
+     * @param {number} start 
+     * @param {number} end 
+     * @returns {string}
+     */
+    getText(start, end) {
+      const { specifier, version } = this;
+      debug(
+        `snapshot.getText(${start}, ${end}) specifier: ${specifier} version: ${version}`,
+      );
+      return core.jsonOpSync("op_get_text", { specifier, version, start, end });
+    }
+    /**
+     * @returns {number}
+     */
+    getLength() {
+      const { specifier, version } = this;
+      debug(`snapshot.getLength() specifier: ${specifier} version: ${version}`);
+      return core.jsonOpSync("op_get_length", { specifier, version });
+    }
+    /**
+     * @param {ScriptSnapshot} oldSnapshot
+     * @returns {ts.TextChangeRange | undefined}
+     */
+    getChangeRange(oldSnapshot) {
+      const { specifier, version } = this;
+      const { version: oldVersion } = oldSnapshot;
+      const oldLength = oldSnapshot.getLength();
+      debug(
+        `snapshot.getLength() specifier: ${specifier} oldVersion: ${oldVersion} version: ${version}`,
+      );
+      return core.jsonOpSync(
+        "op_get_change_range",
+        { specifier, oldLength, oldVersion, version },
+      );
+    }
+    dispose() {
+      const { specifier, version } = this;
+      debug(`snapshot.dispose() specifier: ${specifier} version: ${version}`);
+      core.jsonOpSync("op_dispose", { specifier, version });
+    }
+  }
+
+  /** @type {ts.CompilerOptions} */
+  let compilationSettings = {};
+
+  /** @type {ts.LanguageService} */
+  let languageService;
+
+  /** An object literal of the incremental compiler host, which provides the
+   * specific "bindings" to the Deno environment that tsc needs to work.
+   *
+   * @type {ts.CompilerHost & ts.LanguageServiceHost} */
+  const host = {
+    fileExists(fileName) {
+      debug(`host.fileExists("${fileName}")`);
+      return false;
+    },
+    readFile(specifier) {
+      debug(`host.readFile("${specifier}")`);
+      return core.jsonOpSync("op_load", { specifier }).data;
+    },
+    getSourceFile(
+      specifier,
+      languageVersion,
+      _onError,
+      _shouldCreateNewSourceFile,
+    ) {
+      debug(
+        `host.getSourceFile("${specifier}", ${
+          ts.ScriptTarget[languageVersion]
+        })`,
+      );
+      let sourceFile = sourceFileCache.get(specifier);
+      if (sourceFile) {
+        return sourceFile;
+      }
+
+      /** @type {{ data: string; hash?: string; scriptKind: ts.ScriptKind }} */
+      const { data, hash, scriptKind } = core.jsonOpSync(
+        "op_load",
+        { specifier },
+      );
+      assert(
+        data != null,
+        `"data" is unexpectedly null for "${specifier}".`,
+      );
+      sourceFile = ts.createSourceFile(
+        specifier,
+        data,
+        languageVersion,
+        false,
+        scriptKind,
+      );
+      sourceFile.moduleName = specifier;
+      sourceFile.version = hash;
+      sourceFileCache.set(specifier, sourceFile);
+      return sourceFile;
+    },
+    getDefaultLibFileName() {
+      return `${ASSETS}/lib.esnext.d.ts`;
+    },
+    getDefaultLibLocation() {
+      return ASSETS;
+    },
+    writeFile(fileName, data, _writeByteOrderMark, _onError, sourceFiles) {
+      debug(`host.writeFile("${fileName}")`);
+      let maybeSpecifiers;
+      if (sourceFiles) {
+        maybeSpecifiers = sourceFiles.map((sf) => sf.moduleName);
+      }
+      return core.jsonOpSync(
+        "op_emit",
+        { maybeSpecifiers, fileName, data },
+      );
+    },
+    getCurrentDirectory() {
+      return CACHE;
+    },
+    getCanonicalFileName(fileName) {
+      return fileName;
+    },
+    useCaseSensitiveFileNames() {
+      return true;
+    },
+    getNewLine() {
+      return "\n";
+    },
+    resolveModuleNames(specifiers, base) {
+      debug(`host.resolveModuleNames()`);
+      debug(`  base: ${base}`);
+      debug(`  specifiers: ${specifiers.join(", ")}`);
+      /** @type {Array<[string, ts.Extension] | undefined>} */
+      const resolved = core.jsonOpSync("op_resolve", {
+        specifiers,
+        base,
+      });
+      if (resolved) {
+        const result = resolved.map((item) => {
+          if (item) {
+            const [resolvedFileName, extension] = item;
+            return {
+              resolvedFileName,
+              extension,
+              isExternalLibraryImport: false,
+            };
+          }
+          return undefined;
+        });
+        result.length = specifiers.length;
+        return result;
+      } else {
+        return new Array(specifiers.length);
+      }
+    },
+    createHash(data) {
+      return core.jsonOpSync("op_create_hash", { data }).hash;
+    },
+
+    // LanguageServiceHost
+    getCompilationSettings() {
+      debug("host.getCompilationSettings()");
+      return compilationSettings;
+    },
+    getScriptFileNames() {
+      debug("host.getScriptFileNames()");
+      return core.jsonOpSync("op_script_names", undefined);
+    },
+    getScriptVersion(specifier) {
+      debug(`host.getScriptVersion("${specifier}")`);
+      const sourceFile = sourceFileCache.get(specifier);
+      if (sourceFile) {
+        return sourceFile.version ?? "1";
+      }
+      return core.jsonOpSync("op_script_version", { specifier });
+    },
+    getScriptSnapshot(specifier) {
+      debug(`host.getScriptSnapshot("${specifier}")`);
+      const sourceFile = sourceFileCache.get(specifier);
+      if (sourceFile) {
+        return {
+          getText(start, end) {
+            return sourceFile.text.substring(start, end);
+          },
+          getLength() {
+            return sourceFile.text.length;
+          },
+          getChangeRange() {
+            return undefined;
+          },
+        };
+      }
+      /** @type {string | undefined} */
+      const version = core.jsonOpSync("op_script_version", { specifier });
+      if (version != null) {
+        return new ScriptSnapshot(specifier, version);
+      }
+      return undefined;
+    },
+  };
+
+  /** @type {Array<[string, number]>} */
+  const stats = [];
+  let statsStart = 0;
+
+  function performanceStart() {
+    stats.length = 0;
+    statsStart = Date.now();
+    ts.performance.enable();
+  }
+
+  /**
+   * @param {{ program: ts.Program | ts.EmitAndSemanticDiagnosticsBuilderProgram, fileCount?: number }} options 
+   */
+  function performanceProgram({ program, fileCount }) {
+    if (program) {
+      if ("getProgram" in program) {
+        program = program.getProgram();
+      }
+      stats.push(["Files", program.getSourceFiles().length]);
+      stats.push(["Nodes", program.getNodeCount()]);
+      stats.push(["Identifiers", program.getIdentifierCount()]);
+      stats.push(["Symbols", program.getSymbolCount()]);
+      stats.push(["Types", program.getTypeCount()]);
+      stats.push(["Instantiations", program.getInstantiationCount()]);
+    } else if (fileCount != null) {
+      stats.push(["Files", fileCount]);
+    }
+    const programTime = ts.performance.getDuration("Program");
+    const bindTime = ts.performance.getDuration("Bind");
+    const checkTime = ts.performance.getDuration("Check");
+    const emitTime = ts.performance.getDuration("Emit");
+    stats.push(["Parse time", programTime]);
+    stats.push(["Bind time", bindTime]);
+    stats.push(["Check time", checkTime]);
+    stats.push(["Emit time", emitTime]);
+    stats.push(
+      ["Total TS time", programTime + bindTime + checkTime + emitTime],
+    );
+  }
+
+  function performanceEnd() {
+    const duration = Date.now() - statsStart;
+    stats.push(["Compile time", duration]);
+    return stats;
+  }
+
+  /**
+   * @typedef {object} Request
+   * @property {Record<string, any>} config
+   * @property {boolean} debug
+   * @property {string[]} rootNames
+   */
+
+  /** The API that is called by Rust when executing a request.
+   * @param {Request} request
+   */
+  function exec({ config, debug: debugFlag, rootNames }) {
+    setLogDebug(debugFlag, "TS");
+    performanceStart();
+    debug(">>> exec start", { rootNames });
+    debug(config);
+
+    const { options, errors: configFileParsingDiagnostics } = ts
+      .convertCompilerOptionsFromJson(config, "");
+    // The `allowNonTsExtensions` is a "hidden" compiler option used in VSCode
+    // which is not allowed to be passed in JSON, we need it to allow special
+    // URLs which Deno supports. So we need to either ignore the diagnostic, or
+    // inject it ourselves.
+    Object.assign(options, { allowNonTsExtensions: true });
+    const program = ts.createIncrementalProgram({
+      rootNames,
+      options,
+      host,
+      configFileParsingDiagnostics,
+    });
+
+    const { diagnostics: emitDiagnostics } = program.emit();
+
+    const diagnostics = [
+      ...program.getConfigFileParsingDiagnostics(),
+      ...program.getSyntacticDiagnostics(),
+      ...program.getOptionsDiagnostics(),
+      ...program.getGlobalDiagnostics(),
+      ...program.getSemanticDiagnostics(),
+      ...emitDiagnostics,
+    ].filter(({ code }) => !IGNORED_DIAGNOSTICS.includes(code));
+    performanceProgram({ program });
+
+    core.jsonOpSync("op_respond", {
+      diagnostics: fromTypeScriptDiagnostic(diagnostics),
+      stats: performanceEnd(),
+    });
+    debug("<<< exec stop");
+  }
+
+  /**
+   * @param {number} id 
+   * @param {any} data 
+   */
+  function respond(id, data = null) {
+    core.jsonOpSync("op_respond", { id, data });
+  }
+
+  /**
+   * @param {LanguageServerRequest} request 
+   */
+  function serverRequest({ id, ...request }) {
+    debug(`serverRequest()`, { id, ...request });
+    switch (request.method) {
+      case "configure": {
+        const { options, errors } = ts
+          .convertCompilerOptionsFromJson(request.compilerOptions, "");
+        Object.assign(options, { allowNonTsExtensions: true });
+        if (errors.length) {
+          debug(ts.formatDiagnostics(errors, host));
+        }
+        compilationSettings = options;
+        return respond(id, true);
+      }
+      case "getAsset": {
+        const sourceFile = host.getSourceFile(
+          request.specifier,
+          ts.ScriptTarget.ESNext,
+        );
+        return respond(id, sourceFile && sourceFile.text);
+      }
+      case "getDiagnostics": {
+        try {
+          /** @type {Record<string, any[]>} */
+          const diagnosticMap = {};
+          for (const specifier of request.specifiers) {
+            diagnosticMap[specifier] = fromTypeScriptDiagnostic([
+              ...languageService.getSemanticDiagnostics(specifier),
+              ...languageService.getSuggestionDiagnostics(specifier),
+              ...languageService.getSyntacticDiagnostics(specifier),
+            ].filter(({ code }) => !IGNORED_DIAGNOSTICS.includes(code)));
+          }
+          return respond(id, diagnosticMap);
+        } catch (e) {
+          if ("stack" in e) {
+            error(e.stack);
+          } else {
+            error(e);
+          }
+          return respond(id, {});
+        }
+      }
+      case "getQuickInfo": {
+        return respond(
+          id,
+          languageService.getQuickInfoAtPosition(
+            request.specifier,
+            request.position,
+          ),
+        );
+      }
+      case "getCompletions": {
+        return respond(
+          id,
+          languageService.getCompletionsAtPosition(
+            request.specifier,
+            request.position,
+            request.preferences,
+          ),
+        );
+      }
+      case "getDocumentHighlights": {
+        return respond(
+          id,
+          languageService.getDocumentHighlights(
+            request.specifier,
+            request.position,
+            request.filesToSearch,
+          ),
+        );
+      }
+      case "getReferences": {
+        return respond(
+          id,
+          languageService.getReferencesAtPosition(
+            request.specifier,
+            request.position,
+          ),
+        );
+      }
+      case "getDefinition": {
+        return respond(
+          id,
+          languageService.getDefinitionAndBoundSpan(
+            request.specifier,
+            request.position,
+          ),
+        );
+      }
+      case "getImplementation": {
+        return respond(
+          id,
+          languageService.getImplementationAtPosition(
+            request.specifier,
+            request.position,
+          ),
+        );
+      }
+      case "findRenameLocations": {
+        return respond(
+          id,
+          languageService.findRenameLocations(
+            request.specifier,
+            request.position,
+            request.findInStrings,
+            request.findInComments,
+            request.providePrefixAndSuffixTextForRename,
+          ),
+        );
+      }
+      default:
+        throw new TypeError(
+          // @ts-ignore exhausted case statement sets type to never
+          `Invalid request method for request: "${request.method}" (${id})`,
+        );
+    }
+  }
+
+  /** @param {{ debug: boolean; }} init */
+  function serverInit({ debug: debugFlag }) {
+    if (hasStarted) {
+      throw new Error("The language server has already been initialized.");
+    }
+    hasStarted = true;
+    languageService = ts.createLanguageService(host);
+    core.ops();
+    setLogDebug(debugFlag, "TSLS");
+    debug("serverInit()");
+  }
+
+  let hasStarted = false;
+
+  /** Startup the runtime environment, setting various flags.
+   * @param {{ debugFlag?: boolean; legacyFlag?: boolean; }} msg
+   */
+  function startup({ debugFlag = false }) {
+    if (hasStarted) {
+      throw new Error("The compiler runtime already started.");
+    }
+    hasStarted = true;
+    core.ops();
+    setLogDebug(!!debugFlag, "TS");
+  }
+
+  // Setup the compiler runtime during the build process.
+  core.ops();
+  core.registerErrorClass("Error", Error);
+
+  // A build time only op that provides some setup information that is used to
+  // ensure the snapshot is setup properly.
+  /** @type {{ buildSpecifier: string; libs: string[] }} */
+  const { buildSpecifier, libs } = core.jsonOpSync("op_build_info", {});
+  for (const lib of libs) {
+    const specifier = `lib.${lib}.d.ts`;
+    // we are using internal APIs here to "inject" our custom libraries into
+    // tsc, so things like `"lib": [ "deno.ns" ]` are supported.
+    if (!ts.libs.includes(lib)) {
+      ts.libs.push(lib);
+      ts.libMap.set(lib, `lib.${lib}.d.ts`);
+    }
+    // we are caching in memory common type libraries that will be re-used by
+    // tsc on when the snapshot is restored
+    assert(
+      host.getSourceFile(`${ASSETS}${specifier}`, ts.ScriptTarget.ESNext),
+    );
+  }
+  // this helps ensure as much as possible is in memory that is re-usable
+  // before the snapshotting is done, which helps unsure fast "startup" for
+  // subsequent uses of tsc in Deno.
+  const TS_SNAPSHOT_PROGRAM = ts.createProgram({
+    rootNames: [buildSpecifier],
+    options: SNAPSHOT_COMPILE_OPTIONS,
+    host,
+  });
+  ts.getPreEmitDiagnostics(TS_SNAPSHOT_PROGRAM);
+
+  // exposes the two functions that are called by `tsc::exec()` when type
+  // checking TypeScript.
+  globalThis.startup = startup;
+  globalThis.exec = exec;
+
+  // exposes the functions that are called when the compiler is used as a
+  // language service.
+  globalThis.serverInit = serverInit;
+  globalThis.serverRequest = serverRequest;
+})(this);
diff --git a/cli/tests/testdata/lsp/lib.tsconfig.json b/cli/tests/testdata/lsp/lib.tsconfig.json
deleted file mode 100644
index 8d2ae8a8b3da02..00000000000000
--- a/cli/tests/testdata/lsp/lib.tsconfig.json
+++ /dev/null
@@ -1,5 +0,0 @@
-{
-  "compilerOptions": {
-    "lib": ["deno.ns", "deno.unstable", "dom"]
-  }
-}
diff --git a/cli/tests/testdata/lsp/outgoing_calls_params.json b/cli/tests/testdata/lsp/outgoing_calls_params.json
deleted file mode 100644
index 6b38d26ee59179..00000000000000
--- a/cli/tests/testdata/lsp/outgoing_calls_params.json
+++ /dev/null
@@ -1,28 +0,0 @@
-{
-  "item": {
-    "name": "baz",
-    "kind": 6,
-    "detail": "Bar",
-    "uri": "file:///a/file.ts",
-    "range": {
-      "start": {
-        "line": 5,
-        "character": 2
-      },
-      "end": {
-        "line": 7,
-        "character": 3
-      }
-    },
-    "selectionRange": {
-      "start": {
-        "line": 5,
-        "character": 2
-      },
-      "end": {
-        "line": 5,
-        "character": 5
-      }
-    }
-  }
-}
diff --git a/cli/tests/testdata/lsp/outgoing_calls_response.json b/cli/tests/testdata/lsp/outgoing_calls_response.json
deleted file mode 100644
index c7cf85cf8143b7..00000000000000
--- a/cli/tests/testdata/lsp/outgoing_calls_response.json
+++ /dev/null
@@ -1,42 +0,0 @@
-[
-  {
-    "to": {
-      "name": "foo",
-      "kind": 12,
-      "detail": "",
-      "uri": "file:///a/file.ts",
-      "range": {
-        "start": {
-          "line": 0,
-          "character": 0
-        },
-        "end": {
-          "line": 2,
-          "character": 1
-        }
-      },
-      "selectionRange": {
-        "start": {
-          "line": 0,
-          "character": 9
-        },
-        "end": {
-          "line": 0,
-          "character": 12
-        }
-      }
-    },
-    "fromRanges": [
-      {
-        "start": {
-          "line": 6,
-          "character": 11
-        },
-        "end": {
-          "line": 6,
-          "character": 14
-        }
-      }
-    ]
-  }
-]
diff --git a/cli/tests/testdata/lsp/prepare_call_hierarchy_response.json b/cli/tests/testdata/lsp/prepare_call_hierarchy_response.json
deleted file mode 100644
index 93a7d4f1be8e51..00000000000000
--- a/cli/tests/testdata/lsp/prepare_call_hierarchy_response.json
+++ /dev/null
@@ -1,28 +0,0 @@
-[
-  {
-    "name": "baz",
-    "kind": 6,
-    "detail": "Bar",
-    "uri": "file:///a/file.ts",
-    "range": {
-      "start": {
-        "line": 5,
-        "character": 2
-      },
-      "end": {
-        "line": 7,
-        "character": 3
-      }
-    },
-    "selectionRange": {
-      "start": {
-        "line": 5,
-        "character": 2
-      },
-      "end": {
-        "line": 5,
-        "character": 5
-      }
-    }
-  }
-]
diff --git a/cli/tests/testdata/lsp/rename_response.json b/cli/tests/testdata/lsp/rename_response.json
deleted file mode 100644
index 5e0e28e4c074e2..00000000000000
--- a/cli/tests/testdata/lsp/rename_response.json
+++ /dev/null
@@ -1,38 +0,0 @@
-{
-  "documentChanges": [
-    {
-      "textDocument": {
-        "uri": "file:///a/file.ts",
-        "version": 1
-      },
-      "edits": [
-        {
-          "range": {
-            "start": {
-              "line": 0,
-              "character": 4
-            },
-            "end": {
-              "line": 0,
-              "character": 12
-            }
-          },
-          "newText": "variable_modified"
-        },
-        {
-          "range": {
-            "start": {
-              "line": 1,
-              "character": 12
-            },
-            "end": {
-              "line": 1,
-              "character": 20
-            }
-          },
-          "newText": "variable_modified"
-        }
-      ]
-    }
-  ]
-}
diff --git a/cli/tests/testdata/lsp/selection_range_response.json b/cli/tests/testdata/lsp/selection_range_response.json
deleted file mode 100644
index c5a8b288e27937..00000000000000
--- a/cli/tests/testdata/lsp/selection_range_response.json
+++ /dev/null
@@ -1,98 +0,0 @@
-[
-  {
-    "range": {
-      "start": {
-        "line": 2,
-        "character": 8
-      },
-      "end": {
-        "line": 2,
-        "character": 9
-      }
-    },
-    "parent": {
-      "range": {
-        "start": {
-          "line": 2,
-          "character": 8
-        },
-        "end": {
-          "line": 2,
-          "character": 15
-        }
-      },
-      "parent": {
-        "range": {
-          "start": {
-            "line": 2,
-            "character": 4
-          },
-          "end": {
-            "line": 4,
-            "character": 5
-          }
-        },
-        "parent": {
-          "range": {
-            "start": {
-              "line": 1,
-              "character": 13
-            },
-            "end": {
-              "line": 6,
-              "character": 2
-            }
-          },
-          "parent": {
-            "range": {
-              "start": {
-                "line": 1,
-                "character": 12
-              },
-              "end": {
-                "line": 6,
-                "character": 3
-              }
-            },
-            "parent": {
-              "range": {
-                "start": {
-                  "line": 1,
-                  "character": 2
-                },
-                "end": {
-                  "line": 6,
-                  "character": 3
-                }
-              },
-              "parent": {
-                "range": {
-                  "start": {
-                    "line": 0,
-                    "character": 11
-                  },
-                  "end": {
-                    "line": 7,
-                    "character": 0
-                  }
-                },
-                "parent": {
-                  "range": {
-                    "start": {
-                      "line": 0,
-                      "character": 0
-                    },
-                    "end": {
-                      "line": 7,
-                      "character": 1
-                    }
-                  }
-                }
-              }
-            }
-          }
-        }
-      }
-    }
-  }
-]
diff --git a/test_util/Cargo.toml b/test_util/Cargo.toml
index 93bad8594b85ce..705ccda408dc86 100644
--- a/test_util/Cargo.toml
+++ b/test_util/Cargo.toml
@@ -23,6 +23,7 @@ flate2.workspace = true
 futures.workspace = true
 hyper = { workspace = true, features = ["server", "http1", "http2", "runtime"] }
 lazy_static = "1.4.0"
+lsp-types.workspace = true
 once_cell.workspace = true
 os_pipe.workspace = true
 parking_lot.workspace = true
diff --git a/test_util/src/builders.rs b/test_util/src/builders.rs
index da331b62a17461..e72ce9b63593ad 100644
--- a/test_util/src/builders.rs
+++ b/test_util/src/builders.rs
@@ -18,6 +18,7 @@ use crate::copy_dir_recursive;
 use crate::deno_exe_path;
 use crate::env_vars_for_npm_tests_no_sync_download;
 use crate::http_server;
+use crate::lsp::LspClientBuilder;
 use crate::new_deno_dir;
 use crate::strip_ansi_codes;
 use crate::testdata_path;
@@ -35,6 +36,7 @@ pub struct TestContextBuilder {
   copy_temp_dir: Option<String>,
   cwd: Option<String>,
   envs: HashMap<String, String>,
+  deno_exe: Option<PathBuf>,
 }
 
 impl TestContextBuilder {
@@ -110,7 +112,7 @@ impl TestContextBuilder {
       testdata_path()
     };
 
-    let deno_exe = deno_exe_path();
+    let deno_exe = self.deno_exe.clone().unwrap_or_else(deno_exe_path);
     println!("deno_exe path {}", deno_exe.display());
 
     let http_server_guard = if self.use_http_server {
@@ -121,6 +123,7 @@ impl TestContextBuilder {
 
     TestContext {
       cwd: self.cwd.clone(),
+      deno_exe,
       envs: self.envs.clone(),
       use_temp_cwd: self.use_temp_cwd,
       _http_server_guard: http_server_guard,
@@ -132,6 +135,7 @@ impl TestContextBuilder {
 
 #[derive(Clone)]
 pub struct TestContext {
+  deno_exe: PathBuf,
   envs: HashMap<String, String>,
   use_temp_cwd: bool,
   cwd: Option<String>,
@@ -161,7 +165,7 @@ impl TestContext {
 
   pub fn new_command(&self) -> TestCommandBuilder {
     TestCommandBuilder {
-      command_name: Default::default(),
+      command_name: self.deno_exe.to_string_lossy().to_string(),
       args: Default::default(),
       args_vec: Default::default(),
       stdin: Default::default(),
@@ -172,10 +176,16 @@ impl TestContext {
       context: self.clone(),
     }
   }
+
+  pub fn new_lsp_command(&self) -> LspClientBuilder {
+    let mut builder = LspClientBuilder::new();
+    builder.deno_exe(&self.deno_exe).set_test_context(self);
+    builder
+  }
 }
 
 pub struct TestCommandBuilder {
-  command_name: Option<String>,
+  command_name: String,
   args: String,
   args_vec: Vec<String>,
   stdin: Option<String>,
@@ -188,7 +198,7 @@ pub struct TestCommandBuilder {
 
 impl TestCommandBuilder {
   pub fn command_name(&mut self, name: impl AsRef<str>) -> &mut Self {
-    self.command_name = Some(name.as_ref().to_string());
+    self.command_name = name.as_ref().to_string();
     self
   }
 
@@ -284,15 +294,11 @@ impl TestCommandBuilder {
       arg.replace("$TESTDATA", &self.context.testdata_dir.to_string_lossy())
     })
     .collect::<Vec<_>>();
-    let command_name = self
-      .command_name
-      .as_ref()
-      .cloned()
-      .unwrap_or("deno".to_string());
+    let command_name = &self.command_name;
     let mut command = if command_name == "deno" {
       Command::new(deno_exe_path())
     } else {
-      Command::new(&command_name)
+      Command::new(command_name)
     };
     command.env("DENO_DIR", self.context.deno_dir.path());
 
diff --git a/test_util/src/lsp.rs b/test_util/src/lsp.rs
index c4a81c63c621fe..5798235b678cfa 100644
--- a/test_util/src/lsp.rs
+++ b/test_util/src/lsp.rs
@@ -1,12 +1,29 @@
 // Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
 
+use crate::deno_exe_path;
 use crate::npm_registry_url;
+use crate::TestContext;
+use crate::TestContextBuilder;
 
 use super::new_deno_dir;
 use super::TempDir;
 
 use anyhow::Result;
 use lazy_static::lazy_static;
+use lsp_types::ClientCapabilities;
+use lsp_types::ClientInfo;
+use lsp_types::CodeActionCapabilityResolveSupport;
+use lsp_types::CodeActionClientCapabilities;
+use lsp_types::CodeActionKindLiteralSupport;
+use lsp_types::CodeActionLiteralSupport;
+use lsp_types::CompletionClientCapabilities;
+use lsp_types::CompletionItemCapability;
+use lsp_types::FoldingRangeClientCapabilities;
+use lsp_types::InitializeParams;
+use lsp_types::TextDocumentClientCapabilities;
+use lsp_types::TextDocumentSyncClientCapabilities;
+use lsp_types::Url;
+use lsp_types::WorkspaceClientCapabilities;
 use parking_lot::Condvar;
 use parking_lot::Mutex;
 use regex::Regex;
@@ -19,6 +36,7 @@ use serde_json::Value;
 use std::io;
 use std::io::Write;
 use std::path::Path;
+use std::path::PathBuf;
 use std::process::Child;
 use std::process::ChildStdin;
 use std::process::ChildStdout;
@@ -153,6 +171,335 @@ impl LspStdoutReader {
   }
 }
 
+pub struct InitializeParamsBuilder {
+  params: InitializeParams,
+}
+
+impl InitializeParamsBuilder {
+  #[allow(clippy::new_without_default)]
+  pub fn new() -> Self {
+    Self {
+      params: InitializeParams {
+        process_id: None,
+        client_info: Some(ClientInfo {
+          name: "test-harness".to_string(),
+          version: Some("1.0.0".to_string()),
+        }),
+        root_uri: None,
+        initialization_options: Some(json!({
+          "enable": true,
+          "cache": null,
+          "certificateStores": null,
+          "codeLens": {
+            "implementations": true,
+            "references": true,
+            "test": true
+          },
+          "config": null,
+          "importMap": null,
+          "lint": true,
+          "suggest": {
+            "autoImports": true,
+            "completeFunctionCalls": false,
+            "names": true,
+            "paths": true,
+            "imports": {
+              "hosts": {}
+            }
+          },
+          "testing": {
+            "args": [
+              "--allow-all"
+            ],
+            "enable": true
+          },
+          "tlsCertificate": null,
+          "unsafelyIgnoreCertificateErrors": null,
+          "unstable": false
+        })),
+        capabilities: ClientCapabilities {
+          text_document: Some(TextDocumentClientCapabilities {
+            code_action: Some(CodeActionClientCapabilities {
+              code_action_literal_support: Some(CodeActionLiteralSupport {
+                code_action_kind: CodeActionKindLiteralSupport {
+                  value_set: vec![
+                    "quickfix".to_string(),
+                    "refactor".to_string(),
+                  ],
+                },
+              }),
+              is_preferred_support: Some(true),
+              data_support: Some(true),
+              disabled_support: Some(true),
+              resolve_support: Some(CodeActionCapabilityResolveSupport {
+                properties: vec!["edit".to_string()],
+              }),
+              ..Default::default()
+            }),
+            completion: Some(CompletionClientCapabilities {
+              completion_item: Some(CompletionItemCapability {
+                snippet_support: Some(true),
+                ..Default::default()
+              }),
+              ..Default::default()
+            }),
+            folding_range: Some(FoldingRangeClientCapabilities {
+              line_folding_only: Some(true),
+              ..Default::default()
+            }),
+            synchronization: Some(TextDocumentSyncClientCapabilities {
+              dynamic_registration: Some(true),
+              will_save: Some(true),
+              will_save_wait_until: Some(true),
+              did_save: Some(true),
+            }),
+            ..Default::default()
+          }),
+          workspace: Some(WorkspaceClientCapabilities {
+            configuration: Some(true),
+            workspace_folders: Some(true),
+            ..Default::default()
+          }),
+          experimental: Some(json!({
+            "testingApi": true
+          })),
+          ..Default::default()
+        },
+        ..Default::default()
+      },
+    }
+  }
+
+  pub fn set_maybe_root_uri(&mut self, value: Option<Url>) -> &mut Self {
+    self.params.root_uri = value;
+    self
+  }
+
+  pub fn set_root_uri(&mut self, value: Url) -> &mut Self {
+    self.set_maybe_root_uri(Some(value))
+  }
+
+  pub fn set_workspace_folders(
+    &mut self,
+    folders: Vec<lsp_types::WorkspaceFolder>,
+  ) -> &mut Self {
+    self.params.workspace_folders = Some(folders);
+    self
+  }
+
+  pub fn enable_inlay_hints(&mut self) -> &mut Self {
+    let options = self.initialization_options_mut();
+    options.insert(
+      "inlayHints".to_string(),
+      json!({
+        "parameterNames": {
+          "enabled": "all"
+        },
+        "parameterTypes": {
+          "enabled": true
+        },
+        "variableTypes": {
+          "enabled": true
+        },
+        "propertyDeclarationTypes": {
+          "enabled": true
+        },
+        "functionLikeReturnTypes": {
+          "enabled": true
+        },
+        "enumMemberValues": {
+          "enabled": true
+        }
+      }),
+    );
+    self
+  }
+
+  pub fn disable_testing_api(&mut self) -> &mut Self {
+    let obj = self
+      .params
+      .capabilities
+      .experimental
+      .as_mut()
+      .unwrap()
+      .as_object_mut()
+      .unwrap();
+    obj.insert("testingApi".to_string(), false.into());
+    let options = self.initialization_options_mut();
+    options.remove("testing");
+    self
+  }
+
+  pub fn set_cache(&mut self, value: impl AsRef<str>) -> &mut Self {
+    let options = self.initialization_options_mut();
+    options.insert("cache".to_string(), value.as_ref().to_string().into());
+    self
+  }
+
+  pub fn set_code_lens(
+    &mut self,
+    value: Option<serde_json::Value>,
+  ) -> &mut Self {
+    let options = self.initialization_options_mut();
+    if let Some(value) = value {
+      options.insert("codeLens".to_string(), value);
+    } else {
+      options.remove("codeLens");
+    }
+    self
+  }
+
+  pub fn set_config(&mut self, value: impl AsRef<str>) -> &mut Self {
+    let options = self.initialization_options_mut();
+    options.insert("config".to_string(), value.as_ref().to_string().into());
+    self
+  }
+
+  pub fn set_enable_paths(&mut self, value: Vec<String>) -> &mut Self {
+    let options = self.initialization_options_mut();
+    options.insert("enablePaths".to_string(), value.into());
+    self
+  }
+
+  pub fn set_deno_enable(&mut self, value: bool) -> &mut Self {
+    let options = self.initialization_options_mut();
+    options.insert("enable".to_string(), value.into());
+    self
+  }
+
+  pub fn set_import_map(&mut self, value: impl AsRef<str>) -> &mut Self {
+    let options = self.initialization_options_mut();
+    options.insert("importMap".to_string(), value.as_ref().to_string().into());
+    self
+  }
+
+  pub fn set_tls_certificate(&mut self, value: impl AsRef<str>) -> &mut Self {
+    let options = self.initialization_options_mut();
+    options.insert(
+      "tlsCertificate".to_string(),
+      value.as_ref().to_string().into(),
+    );
+    self
+  }
+
+  pub fn set_unstable(&mut self, value: bool) -> &mut Self {
+    let options = self.initialization_options_mut();
+    options.insert("unstable".to_string(), value.into());
+    self
+  }
+
+  pub fn add_test_server_suggestions(&mut self) -> &mut Self {
+    self.set_suggest_imports_hosts(vec![(
+      "http://localhost:4545/".to_string(),
+      true,
+    )])
+  }
+
+  pub fn set_suggest_imports_hosts(
+    &mut self,
+    values: Vec<(String, bool)>,
+  ) -> &mut Self {
+    let options = self.initialization_options_mut();
+    let suggest = options.get_mut("suggest").unwrap().as_object_mut().unwrap();
+    let imports = suggest.get_mut("imports").unwrap().as_object_mut().unwrap();
+    let hosts = imports.get_mut("hosts").unwrap().as_object_mut().unwrap();
+    hosts.clear();
+    for (key, value) in values {
+      hosts.insert(key, value.into());
+    }
+    self
+  }
+
+  pub fn with_capabilities(
+    &mut self,
+    mut action: impl FnMut(&mut ClientCapabilities),
+  ) -> &mut Self {
+    action(&mut self.params.capabilities);
+    self
+  }
+
+  fn initialization_options_mut(
+    &mut self,
+  ) -> &mut serde_json::Map<String, serde_json::Value> {
+    let options = self.params.initialization_options.as_mut().unwrap();
+    options.as_object_mut().unwrap()
+  }
+
+  pub fn build(&self) -> InitializeParams {
+    self.params.clone()
+  }
+}
+
+pub struct LspClientBuilder {
+  print_stderr: bool,
+  deno_exe: PathBuf,
+  context: Option<TestContext>,
+}
+
+impl LspClientBuilder {
+  #[allow(clippy::new_without_default)]
+  pub fn new() -> Self {
+    Self {
+      print_stderr: false,
+      deno_exe: deno_exe_path(),
+      context: None,
+    }
+  }
+
+  pub fn deno_exe(&mut self, exe_path: impl AsRef<Path>) -> &mut Self {
+    self.deno_exe = exe_path.as_ref().to_path_buf();
+    self
+  }
+
+  pub fn print_stderr(&mut self) -> &mut Self {
+    self.print_stderr = true;
+    self
+  }
+
+  pub fn set_test_context(&mut self, test_context: &TestContext) -> &mut Self {
+    self.context = Some(test_context.clone());
+    self
+  }
+
+  pub fn build(&self) -> LspClient {
+    self.build_result().unwrap()
+  }
+
+  pub fn build_result(&self) -> Result<LspClient> {
+    let deno_dir = new_deno_dir();
+    let mut command = Command::new(&self.deno_exe);
+    command
+      .env("DENO_DIR", deno_dir.path())
+      .env("NPM_CONFIG_REGISTRY", npm_registry_url())
+      .arg("lsp")
+      .stdin(Stdio::piped())
+      .stdout(Stdio::piped());
+    if !self.print_stderr {
+      command.stderr(Stdio::null());
+    }
+    let mut child = command.spawn()?;
+    let stdout = child.stdout.take().unwrap();
+    let buf_reader = io::BufReader::new(stdout);
+    let reader = LspStdoutReader::new(buf_reader);
+
+    let stdin = child.stdin.take().unwrap();
+    let writer = io::BufWriter::new(stdin);
+
+    Ok(LspClient {
+      child,
+      reader,
+      request_id: 1,
+      start: Instant::now(),
+      context: self
+        .context
+        .clone()
+        .unwrap_or_else(|| TestContextBuilder::new().build()),
+      writer,
+      deno_dir,
+    })
+  }
+}
+
 pub struct LspClient {
   child: Child,
   reader: LspStdoutReader,
@@ -160,6 +507,7 @@ pub struct LspClient {
   start: Instant,
   writer: io::BufWriter<ChildStdin>,
   deno_dir: TempDir,
+  context: TestContext,
 }
 
 impl Drop for LspClient {
@@ -228,36 +576,6 @@ where
 }
 
 impl LspClient {
-  pub fn new(deno_exe: &Path, print_stderr: bool) -> Result<Self> {
-    let deno_dir = new_deno_dir();
-    let mut command = Command::new(deno_exe);
-    command
-      .env("DENO_DIR", deno_dir.path())
-      .env("NPM_CONFIG_REGISTRY", npm_registry_url())
-      .arg("lsp")
-      .stdin(Stdio::piped())
-      .stdout(Stdio::piped());
-    if !print_stderr {
-      command.stderr(Stdio::null());
-    }
-    let mut child = command.spawn()?;
-    let stdout = child.stdout.take().unwrap();
-    let buf_reader = io::BufReader::new(stdout);
-    let reader = LspStdoutReader::new(buf_reader);
-
-    let stdin = child.stdin.take().unwrap();
-    let writer = io::BufWriter::new(stdin);
-
-    Ok(Self {
-      child,
-      reader,
-      request_id: 1,
-      start: Instant::now(),
-      writer,
-      deno_dir,
-    })
-  }
-
   pub fn deno_dir(&self) -> &TempDir {
     &self.deno_dir
   }
@@ -274,6 +592,30 @@ impl LspClient {
     self.reader.pending_len()
   }
 
+  pub fn initialize_default(&mut self) {
+    self.initialize(|_| {})
+  }
+
+  pub fn initialize(
+    &mut self,
+    do_build: impl Fn(&mut InitializeParamsBuilder),
+  ) {
+    let mut builder = InitializeParamsBuilder::new();
+    builder.set_root_uri(self.context.deno_dir().uri());
+    do_build(&mut builder);
+    self
+      .write_request::<_, _, Value>("initialize", builder.build())
+      .unwrap();
+    self.write_notification("initialized", json!({})).unwrap();
+  }
+
+  pub fn shutdown(&mut self) {
+    self
+      .write_request::<_, _, Value>("shutdown", json!(null))
+      .unwrap();
+    self.write_notification("exit", json!(null)).unwrap();
+  }
+
   // it's flaky to assert for a notification because a notification
   // might arrive a little later, so only provide a method for asserting
   // that there is no notification
diff --git a/test_util/src/temp_dir.rs b/test_util/src/temp_dir.rs
index 01dce8f1ab434f..b800e425d2a4fc 100644
--- a/test_util/src/temp_dir.rs
+++ b/test_util/src/temp_dir.rs
@@ -9,6 +9,7 @@ use std::sync::Arc;
 use std::time::SystemTime;
 
 use anyhow::Context;
+use lsp_types::Url;
 use once_cell::sync::OnceCell;
 
 static TEMP_DIR_SESSION: OnceCell<TempDirSession> = OnceCell::new();
@@ -83,6 +84,10 @@ impl TempDir {
     })
   }
 
+  pub fn uri(&self) -> Url {
+    Url::from_directory_path(self.path()).unwrap()
+  }
+
   pub fn path(&self) -> &Path {
     let inner = &self.0;
     inner.0.as_path()