diff --git a/compiler/rustc_codegen_cranelift/build_system/tests.rs b/compiler/rustc_codegen_cranelift/build_system/tests.rs
index 8de419a0c4eb2..bcb2b4881ebe4 100644
--- a/compiler/rustc_codegen_cranelift/build_system/tests.rs
+++ b/compiler/rustc_codegen_cranelift/build_system/tests.rs
@@ -151,7 +151,7 @@ const EXTENDED_SYSROOT_SUITE: &[TestCase] = &[
         apply_patches(
             &runner.dirs,
             "coretests",
-            &runner.stdlib_source.join("library/core/tests"),
+            &runner.stdlib_source.join("library/coretests"),
             &LIBCORE_TESTS_SRC.to_path(&runner.dirs),
         );
 
diff --git a/compiler/rustc_codegen_cranelift/patches/0022-coretests-Disable-not-compiling-tests.patch b/compiler/rustc_codegen_cranelift/patches/0022-coretests-Disable-not-compiling-tests.patch
deleted file mode 100644
index 161173d47650f..0000000000000
--- a/compiler/rustc_codegen_cranelift/patches/0022-coretests-Disable-not-compiling-tests.patch
+++ /dev/null
@@ -1,44 +0,0 @@
-From f6befc4bb51d84f5f1cf35938a168c953d421350 Mon Sep 17 00:00:00 2001
-From: bjorn3 <bjorn3@users.noreply.github.com>
-Date: Sun, 24 Nov 2019 15:10:23 +0100
-Subject: [PATCH] [core] Disable not compiling tests
-
----
- library/core/tests/Cargo.toml         | 8 ++++++++
- library/core/tests/num/flt2dec/mod.rs | 1 -
- library/core/tests/num/int_macros.rs  | 2 ++
- library/core/tests/num/uint_macros.rs | 2 ++
- library/core/tests/ptr.rs             | 2 ++
- library/core/tests/slice.rs           | 2 ++
- 6 files changed, 16 insertions(+), 1 deletion(-)
- create mode 100644 library/core/tests/Cargo.toml
-
-diff --git a/Cargo.toml b/Cargo.toml
-new file mode 100644
-index 0000000..46fd999
---- /dev/null
-+++ b/Cargo.toml
-@@ -0,0 +1,12 @@
-+[package]
-+name = "coretests"
-+version = "0.0.0"
-+edition = "2021"
-+
-+[lib]
-+name = "coretests"
-+path = "lib.rs"
-+
-+[dependencies]
-+rand = { version = "0.8.5", default-features = false }
-+rand_xorshift = { version = "0.3.0", default-features = false }
-diff --git a/lib.rs b/lib.rs
-index 42a26ae..5ac1042 100644
---- a/lib.rs
-+++ b/lib.rs
-@@ -1,3 +1,4 @@
-+#![cfg(test)]
- // tidy-alphabetical-start
- #![cfg_attr(target_has_atomic = "128", feature(integer_atomics))]
- #![cfg_attr(test, feature(cfg_match))]
---
-2.21.0 (Apple Git-122)
diff --git a/compiler/rustc_codegen_cranelift/patches/0027-coretests-128bit-atomic-operations.patch b/compiler/rustc_codegen_cranelift/patches/0027-coretests-128bit-atomic-operations.patch
index 06840624ceffe..4a06dc3f7ef85 100644
--- a/compiler/rustc_codegen_cranelift/patches/0027-coretests-128bit-atomic-operations.patch
+++ b/compiler/rustc_codegen_cranelift/patches/0027-coretests-128bit-atomic-operations.patch
@@ -10,21 +10,20 @@ Cranelift doesn't support them yet
  library/core/tests/atomic.rs          |  4 ---
  4 files changed, 4 insertions(+), 50 deletions(-)
 
-diff --git a/lib.rs b/lib.rs
+diff --git a/tests/lib.rs b/tests/lib.rs
 index 1e336bf..35e6f54 100644
---- a/lib.rs
-+++ b/lib.rs
-@@ -2,6 +2,5 @@
- #![cfg(test)]
+--- a/tests/lib.rs
++++ b/tests/lib.rs
+@@ -2,5 +2,4 @@
  // tidy-alphabetical-start
 -#![cfg_attr(target_has_atomic = "128", feature(integer_atomics))]
  #![cfg_attr(test, feature(cfg_match))]
  #![feature(alloc_layout_extra)]
  #![feature(array_chunks)]
-diff --git a/atomic.rs b/atomic.rs
+diff --git a/tests/atomic.rs b/tests/atomic.rs
 index b735957..ea728b6 100644
---- a/atomic.rs
-+++ b/atomic.rs
+--- a/tests/atomic.rs
++++ b/tests/atomic.rs
 @@ -185,10 +185,6 @@ fn atomic_alignment() {
      assert_eq!(align_of::<AtomicU64>(), size_of::<AtomicU64>());
      #[cfg(target_has_atomic = "64")]
diff --git a/compiler/rustc_codegen_cranelift/patches/0028-coretests-Disable-long-running-tests.patch b/compiler/rustc_codegen_cranelift/patches/0028-coretests-Disable-long-running-tests.patch
index b98326c54a67a..5a38dffa24fe0 100644
--- a/compiler/rustc_codegen_cranelift/patches/0028-coretests-Disable-long-running-tests.patch
+++ b/compiler/rustc_codegen_cranelift/patches/0028-coretests-Disable-long-running-tests.patch
@@ -7,10 +7,10 @@ Subject: [PATCH] Disable long running tests
  library/core/tests/slice.rs | 2 ++
  1 file changed, 2 insertions(+)
 
-diff --git a/slice.rs b/slice.rs
+diff --git a/tests/slice.rs b/tests/slice.rs
 index 8402833..84592e0 100644
---- a/slice.rs
-+++ b/slice.rs
+--- a/tests/slice.rs
++++ b/tests/slice.rs
 @@ -1809,6 +1809,7 @@ fn sort_unstable() {
      }
  }
diff --git a/library/Cargo.lock b/library/Cargo.lock
index 7b9081d46a056..30875482dc06e 100644
--- a/library/Cargo.lock
+++ b/library/Cargo.lock
@@ -72,6 +72,10 @@ dependencies = [
 [[package]]
 name = "core"
 version = "0.0.0"
+
+[[package]]
+name = "coretests"
+version = "0.0.0"
 dependencies = [
  "rand",
  "rand_xorshift",
diff --git a/library/Cargo.toml b/library/Cargo.toml
index e59aa518804f3..1205f7c9ed6b5 100644
--- a/library/Cargo.toml
+++ b/library/Cargo.toml
@@ -3,6 +3,7 @@ resolver = "1"
 members = [
   "std",
   "sysroot",
+  "coretests",
 ]
 
 exclude = [
diff --git a/library/core/Cargo.toml b/library/core/Cargo.toml
index 46c55c437cce5..b7c6db6c78dde 100644
--- a/library/core/Cargo.toml
+++ b/library/core/Cargo.toml
@@ -15,19 +15,6 @@ edition = "2021"
 test = false
 bench = false
 
-[[test]]
-name = "coretests"
-path = "tests/lib.rs"
-
-[[bench]]
-name = "corebenches"
-path = "benches/lib.rs"
-test = true
-
-[dev-dependencies]
-rand = { version = "0.8.5", default-features = false }
-rand_xorshift = { version = "0.3.0", default-features = false }
-
 [features]
 # Make panics and failed asserts immediately abort without formatting any message
 panic_immediate_abort = []
diff --git a/library/core/src/lib.rs b/library/core/src/lib.rs
index 01ed3cc69a2cc..c18e0405f7293 100644
--- a/library/core/src/lib.rs
+++ b/library/core/src/lib.rs
@@ -44,7 +44,7 @@
 //!    called. The `lang` attribute is called `eh_personality`.
 
 // Since core defines many fundamental lang items, all tests live in a
-// separate crate, libcoretest (library/core/tests), to avoid bizarre issues.
+// separate crate, coretests (library/coretests), to avoid bizarre issues.
 //
 // Here we explicitly #[cfg]-out this whole crate when testing. If we don't do
 // this, both the generated test artifact and the linked libtest (which
diff --git a/library/coretests/Cargo.toml b/library/coretests/Cargo.toml
new file mode 100644
index 0000000000000..ec940abea1171
--- /dev/null
+++ b/library/coretests/Cargo.toml
@@ -0,0 +1,27 @@
+[package]
+name = "coretests"
+version = "0.0.0"
+license = "MIT OR Apache-2.0"
+repository = "https://github.com/rust-lang/rust.git"
+description = "Tests for the Rust Core Library"
+autotests = false
+autobenches = false
+edition = "2021"
+
+[lib]
+path = "lib.rs"
+test = false
+bench = false
+
+[[test]]
+name = "coretests"
+path = "tests/lib.rs"
+
+[[bench]]
+name = "corebenches"
+path = "benches/lib.rs"
+test = true
+
+[dev-dependencies]
+rand = { version = "0.8.5", default-features = false }
+rand_xorshift = { version = "0.3.0", default-features = false }
diff --git a/library/core/benches/any.rs b/library/coretests/benches/any.rs
similarity index 100%
rename from library/core/benches/any.rs
rename to library/coretests/benches/any.rs
diff --git a/library/core/benches/array.rs b/library/coretests/benches/array.rs
similarity index 100%
rename from library/core/benches/array.rs
rename to library/coretests/benches/array.rs
diff --git a/library/core/benches/ascii.rs b/library/coretests/benches/ascii.rs
similarity index 100%
rename from library/core/benches/ascii.rs
rename to library/coretests/benches/ascii.rs
diff --git a/library/core/benches/ascii/is_ascii.rs b/library/coretests/benches/ascii/is_ascii.rs
similarity index 100%
rename from library/core/benches/ascii/is_ascii.rs
rename to library/coretests/benches/ascii/is_ascii.rs
diff --git a/library/core/benches/char/methods.rs b/library/coretests/benches/char/methods.rs
similarity index 100%
rename from library/core/benches/char/methods.rs
rename to library/coretests/benches/char/methods.rs
diff --git a/library/core/benches/char/mod.rs b/library/coretests/benches/char/mod.rs
similarity index 100%
rename from library/core/benches/char/mod.rs
rename to library/coretests/benches/char/mod.rs
diff --git a/library/core/benches/fmt.rs b/library/coretests/benches/fmt.rs
similarity index 100%
rename from library/core/benches/fmt.rs
rename to library/coretests/benches/fmt.rs
diff --git a/library/core/benches/hash/mod.rs b/library/coretests/benches/hash/mod.rs
similarity index 100%
rename from library/core/benches/hash/mod.rs
rename to library/coretests/benches/hash/mod.rs
diff --git a/library/core/benches/hash/sip.rs b/library/coretests/benches/hash/sip.rs
similarity index 100%
rename from library/core/benches/hash/sip.rs
rename to library/coretests/benches/hash/sip.rs
diff --git a/library/core/benches/iter.rs b/library/coretests/benches/iter.rs
similarity index 100%
rename from library/core/benches/iter.rs
rename to library/coretests/benches/iter.rs
diff --git a/library/core/benches/lib.rs b/library/coretests/benches/lib.rs
similarity index 100%
rename from library/core/benches/lib.rs
rename to library/coretests/benches/lib.rs
diff --git a/library/core/benches/net/addr_parser.rs b/library/coretests/benches/net/addr_parser.rs
similarity index 100%
rename from library/core/benches/net/addr_parser.rs
rename to library/coretests/benches/net/addr_parser.rs
diff --git a/library/core/benches/net/mod.rs b/library/coretests/benches/net/mod.rs
similarity index 100%
rename from library/core/benches/net/mod.rs
rename to library/coretests/benches/net/mod.rs
diff --git a/library/core/benches/num/dec2flt/mod.rs b/library/coretests/benches/num/dec2flt/mod.rs
similarity index 100%
rename from library/core/benches/num/dec2flt/mod.rs
rename to library/coretests/benches/num/dec2flt/mod.rs
diff --git a/library/core/benches/num/flt2dec/mod.rs b/library/coretests/benches/num/flt2dec/mod.rs
similarity index 100%
rename from library/core/benches/num/flt2dec/mod.rs
rename to library/coretests/benches/num/flt2dec/mod.rs
diff --git a/library/core/benches/num/flt2dec/strategy/dragon.rs b/library/coretests/benches/num/flt2dec/strategy/dragon.rs
similarity index 100%
rename from library/core/benches/num/flt2dec/strategy/dragon.rs
rename to library/coretests/benches/num/flt2dec/strategy/dragon.rs
diff --git a/library/core/benches/num/flt2dec/strategy/grisu.rs b/library/coretests/benches/num/flt2dec/strategy/grisu.rs
similarity index 100%
rename from library/core/benches/num/flt2dec/strategy/grisu.rs
rename to library/coretests/benches/num/flt2dec/strategy/grisu.rs
diff --git a/library/core/benches/num/int_log/mod.rs b/library/coretests/benches/num/int_log/mod.rs
similarity index 100%
rename from library/core/benches/num/int_log/mod.rs
rename to library/coretests/benches/num/int_log/mod.rs
diff --git a/library/core/benches/num/int_pow/mod.rs b/library/coretests/benches/num/int_pow/mod.rs
similarity index 100%
rename from library/core/benches/num/int_pow/mod.rs
rename to library/coretests/benches/num/int_pow/mod.rs
diff --git a/library/core/benches/num/int_sqrt/mod.rs b/library/coretests/benches/num/int_sqrt/mod.rs
similarity index 100%
rename from library/core/benches/num/int_sqrt/mod.rs
rename to library/coretests/benches/num/int_sqrt/mod.rs
diff --git a/library/core/benches/num/mod.rs b/library/coretests/benches/num/mod.rs
similarity index 100%
rename from library/core/benches/num/mod.rs
rename to library/coretests/benches/num/mod.rs
diff --git a/library/core/benches/ops.rs b/library/coretests/benches/ops.rs
similarity index 100%
rename from library/core/benches/ops.rs
rename to library/coretests/benches/ops.rs
diff --git a/library/core/benches/pattern.rs b/library/coretests/benches/pattern.rs
similarity index 100%
rename from library/core/benches/pattern.rs
rename to library/coretests/benches/pattern.rs
diff --git a/library/core/benches/slice.rs b/library/coretests/benches/slice.rs
similarity index 100%
rename from library/core/benches/slice.rs
rename to library/coretests/benches/slice.rs
diff --git a/library/core/benches/str.rs b/library/coretests/benches/str.rs
similarity index 100%
rename from library/core/benches/str.rs
rename to library/coretests/benches/str.rs
diff --git a/library/core/benches/str/char_count.rs b/library/coretests/benches/str/char_count.rs
similarity index 100%
rename from library/core/benches/str/char_count.rs
rename to library/coretests/benches/str/char_count.rs
diff --git a/library/core/benches/str/corpora.rs b/library/coretests/benches/str/corpora.rs
similarity index 100%
rename from library/core/benches/str/corpora.rs
rename to library/coretests/benches/str/corpora.rs
diff --git a/library/core/benches/str/debug.rs b/library/coretests/benches/str/debug.rs
similarity index 100%
rename from library/core/benches/str/debug.rs
rename to library/coretests/benches/str/debug.rs
diff --git a/library/core/benches/str/iter.rs b/library/coretests/benches/str/iter.rs
similarity index 100%
rename from library/core/benches/str/iter.rs
rename to library/coretests/benches/str/iter.rs
diff --git a/library/core/benches/tuple.rs b/library/coretests/benches/tuple.rs
similarity index 100%
rename from library/core/benches/tuple.rs
rename to library/coretests/benches/tuple.rs
diff --git a/library/coretests/lib.rs b/library/coretests/lib.rs
new file mode 100644
index 0000000000000..b49208cd4eb3a
--- /dev/null
+++ b/library/coretests/lib.rs
@@ -0,0 +1 @@
+// Intentionally left empty.
diff --git a/library/core/tests/alloc.rs b/library/coretests/tests/alloc.rs
similarity index 100%
rename from library/core/tests/alloc.rs
rename to library/coretests/tests/alloc.rs
diff --git a/library/core/tests/any.rs b/library/coretests/tests/any.rs
similarity index 100%
rename from library/core/tests/any.rs
rename to library/coretests/tests/any.rs
diff --git a/library/core/tests/array.rs b/library/coretests/tests/array.rs
similarity index 100%
rename from library/core/tests/array.rs
rename to library/coretests/tests/array.rs
diff --git a/library/core/tests/ascii.rs b/library/coretests/tests/ascii.rs
similarity index 100%
rename from library/core/tests/ascii.rs
rename to library/coretests/tests/ascii.rs
diff --git a/library/core/tests/ascii_char.rs b/library/coretests/tests/ascii_char.rs
similarity index 100%
rename from library/core/tests/ascii_char.rs
rename to library/coretests/tests/ascii_char.rs
diff --git a/library/core/tests/asserting.rs b/library/coretests/tests/asserting.rs
similarity index 100%
rename from library/core/tests/asserting.rs
rename to library/coretests/tests/asserting.rs
diff --git a/library/core/tests/async_iter/mod.rs b/library/coretests/tests/async_iter/mod.rs
similarity index 100%
rename from library/core/tests/async_iter/mod.rs
rename to library/coretests/tests/async_iter/mod.rs
diff --git a/library/core/tests/atomic.rs b/library/coretests/tests/atomic.rs
similarity index 100%
rename from library/core/tests/atomic.rs
rename to library/coretests/tests/atomic.rs
diff --git a/library/core/tests/bool.rs b/library/coretests/tests/bool.rs
similarity index 100%
rename from library/core/tests/bool.rs
rename to library/coretests/tests/bool.rs
diff --git a/library/core/tests/bstr.rs b/library/coretests/tests/bstr.rs
similarity index 98%
rename from library/core/tests/bstr.rs
rename to library/coretests/tests/bstr.rs
index 5fecd0a4084c7..cd4d69d6b337d 100644
--- a/library/core/tests/bstr.rs
+++ b/library/coretests/tests/bstr.rs
@@ -1,6 +1,4 @@
-#![feature(bstr)]
-
-use core::ByteStr;
+use core::bstr::ByteStr;
 
 #[test]
 fn test_debug() {
diff --git a/library/core/tests/cell.rs b/library/coretests/tests/cell.rs
similarity index 100%
rename from library/core/tests/cell.rs
rename to library/coretests/tests/cell.rs
diff --git a/library/core/tests/char.rs b/library/coretests/tests/char.rs
similarity index 100%
rename from library/core/tests/char.rs
rename to library/coretests/tests/char.rs
diff --git a/library/core/tests/clone.rs b/library/coretests/tests/clone.rs
similarity index 100%
rename from library/core/tests/clone.rs
rename to library/coretests/tests/clone.rs
diff --git a/library/core/tests/cmp.rs b/library/coretests/tests/cmp.rs
similarity index 100%
rename from library/core/tests/cmp.rs
rename to library/coretests/tests/cmp.rs
diff --git a/library/core/tests/const_ptr.rs b/library/coretests/tests/const_ptr.rs
similarity index 100%
rename from library/core/tests/const_ptr.rs
rename to library/coretests/tests/const_ptr.rs
diff --git a/library/core/tests/convert.rs b/library/coretests/tests/convert.rs
similarity index 100%
rename from library/core/tests/convert.rs
rename to library/coretests/tests/convert.rs
diff --git a/library/core/tests/error.rs b/library/coretests/tests/error.rs
similarity index 100%
rename from library/core/tests/error.rs
rename to library/coretests/tests/error.rs
diff --git a/library/core/tests/ffi.rs b/library/coretests/tests/ffi.rs
similarity index 100%
rename from library/core/tests/ffi.rs
rename to library/coretests/tests/ffi.rs
diff --git a/library/core/tests/ffi/cstr.rs b/library/coretests/tests/ffi/cstr.rs
similarity index 100%
rename from library/core/tests/ffi/cstr.rs
rename to library/coretests/tests/ffi/cstr.rs
diff --git a/library/core/tests/fmt/builders.rs b/library/coretests/tests/fmt/builders.rs
similarity index 100%
rename from library/core/tests/fmt/builders.rs
rename to library/coretests/tests/fmt/builders.rs
diff --git a/library/core/tests/fmt/float.rs b/library/coretests/tests/fmt/float.rs
similarity index 100%
rename from library/core/tests/fmt/float.rs
rename to library/coretests/tests/fmt/float.rs
diff --git a/library/core/tests/fmt/mod.rs b/library/coretests/tests/fmt/mod.rs
similarity index 100%
rename from library/core/tests/fmt/mod.rs
rename to library/coretests/tests/fmt/mod.rs
diff --git a/library/core/tests/fmt/num.rs b/library/coretests/tests/fmt/num.rs
similarity index 100%
rename from library/core/tests/fmt/num.rs
rename to library/coretests/tests/fmt/num.rs
diff --git a/library/core/tests/future.rs b/library/coretests/tests/future.rs
similarity index 100%
rename from library/core/tests/future.rs
rename to library/coretests/tests/future.rs
diff --git a/library/core/tests/hash/mod.rs b/library/coretests/tests/hash/mod.rs
similarity index 100%
rename from library/core/tests/hash/mod.rs
rename to library/coretests/tests/hash/mod.rs
diff --git a/library/core/tests/hash/sip.rs b/library/coretests/tests/hash/sip.rs
similarity index 100%
rename from library/core/tests/hash/sip.rs
rename to library/coretests/tests/hash/sip.rs
diff --git a/library/core/tests/intrinsics.rs b/library/coretests/tests/intrinsics.rs
similarity index 100%
rename from library/core/tests/intrinsics.rs
rename to library/coretests/tests/intrinsics.rs
diff --git a/library/core/tests/io/borrowed_buf.rs b/library/coretests/tests/io/borrowed_buf.rs
similarity index 100%
rename from library/core/tests/io/borrowed_buf.rs
rename to library/coretests/tests/io/borrowed_buf.rs
diff --git a/library/core/tests/io/mod.rs b/library/coretests/tests/io/mod.rs
similarity index 100%
rename from library/core/tests/io/mod.rs
rename to library/coretests/tests/io/mod.rs
diff --git a/library/core/tests/iter/adapters/array_chunks.rs b/library/coretests/tests/iter/adapters/array_chunks.rs
similarity index 100%
rename from library/core/tests/iter/adapters/array_chunks.rs
rename to library/coretests/tests/iter/adapters/array_chunks.rs
diff --git a/library/core/tests/iter/adapters/by_ref_sized.rs b/library/coretests/tests/iter/adapters/by_ref_sized.rs
similarity index 100%
rename from library/core/tests/iter/adapters/by_ref_sized.rs
rename to library/coretests/tests/iter/adapters/by_ref_sized.rs
diff --git a/library/core/tests/iter/adapters/chain.rs b/library/coretests/tests/iter/adapters/chain.rs
similarity index 100%
rename from library/core/tests/iter/adapters/chain.rs
rename to library/coretests/tests/iter/adapters/chain.rs
diff --git a/library/core/tests/iter/adapters/cloned.rs b/library/coretests/tests/iter/adapters/cloned.rs
similarity index 100%
rename from library/core/tests/iter/adapters/cloned.rs
rename to library/coretests/tests/iter/adapters/cloned.rs
diff --git a/library/core/tests/iter/adapters/copied.rs b/library/coretests/tests/iter/adapters/copied.rs
similarity index 100%
rename from library/core/tests/iter/adapters/copied.rs
rename to library/coretests/tests/iter/adapters/copied.rs
diff --git a/library/core/tests/iter/adapters/cycle.rs b/library/coretests/tests/iter/adapters/cycle.rs
similarity index 100%
rename from library/core/tests/iter/adapters/cycle.rs
rename to library/coretests/tests/iter/adapters/cycle.rs
diff --git a/library/core/tests/iter/adapters/enumerate.rs b/library/coretests/tests/iter/adapters/enumerate.rs
similarity index 100%
rename from library/core/tests/iter/adapters/enumerate.rs
rename to library/coretests/tests/iter/adapters/enumerate.rs
diff --git a/library/core/tests/iter/adapters/filter.rs b/library/coretests/tests/iter/adapters/filter.rs
similarity index 100%
rename from library/core/tests/iter/adapters/filter.rs
rename to library/coretests/tests/iter/adapters/filter.rs
diff --git a/library/core/tests/iter/adapters/filter_map.rs b/library/coretests/tests/iter/adapters/filter_map.rs
similarity index 100%
rename from library/core/tests/iter/adapters/filter_map.rs
rename to library/coretests/tests/iter/adapters/filter_map.rs
diff --git a/library/core/tests/iter/adapters/flat_map.rs b/library/coretests/tests/iter/adapters/flat_map.rs
similarity index 100%
rename from library/core/tests/iter/adapters/flat_map.rs
rename to library/coretests/tests/iter/adapters/flat_map.rs
diff --git a/library/core/tests/iter/adapters/flatten.rs b/library/coretests/tests/iter/adapters/flatten.rs
similarity index 100%
rename from library/core/tests/iter/adapters/flatten.rs
rename to library/coretests/tests/iter/adapters/flatten.rs
diff --git a/library/core/tests/iter/adapters/fuse.rs b/library/coretests/tests/iter/adapters/fuse.rs
similarity index 100%
rename from library/core/tests/iter/adapters/fuse.rs
rename to library/coretests/tests/iter/adapters/fuse.rs
diff --git a/library/core/tests/iter/adapters/inspect.rs b/library/coretests/tests/iter/adapters/inspect.rs
similarity index 100%
rename from library/core/tests/iter/adapters/inspect.rs
rename to library/coretests/tests/iter/adapters/inspect.rs
diff --git a/library/core/tests/iter/adapters/intersperse.rs b/library/coretests/tests/iter/adapters/intersperse.rs
similarity index 100%
rename from library/core/tests/iter/adapters/intersperse.rs
rename to library/coretests/tests/iter/adapters/intersperse.rs
diff --git a/library/core/tests/iter/adapters/map.rs b/library/coretests/tests/iter/adapters/map.rs
similarity index 100%
rename from library/core/tests/iter/adapters/map.rs
rename to library/coretests/tests/iter/adapters/map.rs
diff --git a/library/core/tests/iter/adapters/map_windows.rs b/library/coretests/tests/iter/adapters/map_windows.rs
similarity index 100%
rename from library/core/tests/iter/adapters/map_windows.rs
rename to library/coretests/tests/iter/adapters/map_windows.rs
diff --git a/library/core/tests/iter/adapters/mod.rs b/library/coretests/tests/iter/adapters/mod.rs
similarity index 100%
rename from library/core/tests/iter/adapters/mod.rs
rename to library/coretests/tests/iter/adapters/mod.rs
diff --git a/library/core/tests/iter/adapters/peekable.rs b/library/coretests/tests/iter/adapters/peekable.rs
similarity index 100%
rename from library/core/tests/iter/adapters/peekable.rs
rename to library/coretests/tests/iter/adapters/peekable.rs
diff --git a/library/core/tests/iter/adapters/scan.rs b/library/coretests/tests/iter/adapters/scan.rs
similarity index 100%
rename from library/core/tests/iter/adapters/scan.rs
rename to library/coretests/tests/iter/adapters/scan.rs
diff --git a/library/core/tests/iter/adapters/skip.rs b/library/coretests/tests/iter/adapters/skip.rs
similarity index 100%
rename from library/core/tests/iter/adapters/skip.rs
rename to library/coretests/tests/iter/adapters/skip.rs
diff --git a/library/core/tests/iter/adapters/skip_while.rs b/library/coretests/tests/iter/adapters/skip_while.rs
similarity index 100%
rename from library/core/tests/iter/adapters/skip_while.rs
rename to library/coretests/tests/iter/adapters/skip_while.rs
diff --git a/library/core/tests/iter/adapters/step_by.rs b/library/coretests/tests/iter/adapters/step_by.rs
similarity index 100%
rename from library/core/tests/iter/adapters/step_by.rs
rename to library/coretests/tests/iter/adapters/step_by.rs
diff --git a/library/core/tests/iter/adapters/take.rs b/library/coretests/tests/iter/adapters/take.rs
similarity index 100%
rename from library/core/tests/iter/adapters/take.rs
rename to library/coretests/tests/iter/adapters/take.rs
diff --git a/library/core/tests/iter/adapters/take_while.rs b/library/coretests/tests/iter/adapters/take_while.rs
similarity index 100%
rename from library/core/tests/iter/adapters/take_while.rs
rename to library/coretests/tests/iter/adapters/take_while.rs
diff --git a/library/core/tests/iter/adapters/zip.rs b/library/coretests/tests/iter/adapters/zip.rs
similarity index 100%
rename from library/core/tests/iter/adapters/zip.rs
rename to library/coretests/tests/iter/adapters/zip.rs
diff --git a/library/core/tests/iter/mod.rs b/library/coretests/tests/iter/mod.rs
similarity index 100%
rename from library/core/tests/iter/mod.rs
rename to library/coretests/tests/iter/mod.rs
diff --git a/library/core/tests/iter/range.rs b/library/coretests/tests/iter/range.rs
similarity index 100%
rename from library/core/tests/iter/range.rs
rename to library/coretests/tests/iter/range.rs
diff --git a/library/core/tests/iter/sources.rs b/library/coretests/tests/iter/sources.rs
similarity index 100%
rename from library/core/tests/iter/sources.rs
rename to library/coretests/tests/iter/sources.rs
diff --git a/library/core/tests/iter/traits/accum.rs b/library/coretests/tests/iter/traits/accum.rs
similarity index 100%
rename from library/core/tests/iter/traits/accum.rs
rename to library/coretests/tests/iter/traits/accum.rs
diff --git a/library/core/tests/iter/traits/double_ended.rs b/library/coretests/tests/iter/traits/double_ended.rs
similarity index 100%
rename from library/core/tests/iter/traits/double_ended.rs
rename to library/coretests/tests/iter/traits/double_ended.rs
diff --git a/library/core/tests/iter/traits/iterator.rs b/library/coretests/tests/iter/traits/iterator.rs
similarity index 100%
rename from library/core/tests/iter/traits/iterator.rs
rename to library/coretests/tests/iter/traits/iterator.rs
diff --git a/library/core/tests/iter/traits/mod.rs b/library/coretests/tests/iter/traits/mod.rs
similarity index 100%
rename from library/core/tests/iter/traits/mod.rs
rename to library/coretests/tests/iter/traits/mod.rs
diff --git a/library/core/tests/iter/traits/step.rs b/library/coretests/tests/iter/traits/step.rs
similarity index 100%
rename from library/core/tests/iter/traits/step.rs
rename to library/coretests/tests/iter/traits/step.rs
diff --git a/library/core/tests/lazy.rs b/library/coretests/tests/lazy.rs
similarity index 100%
rename from library/core/tests/lazy.rs
rename to library/coretests/tests/lazy.rs
diff --git a/library/core/tests/lib.rs b/library/coretests/tests/lib.rs
similarity index 99%
rename from library/core/tests/lib.rs
rename to library/coretests/tests/lib.rs
index a8980c5f30aec..0607d508a48e5 100644
--- a/library/core/tests/lib.rs
+++ b/library/coretests/tests/lib.rs
@@ -11,6 +11,7 @@
 #![feature(async_iter_from_iter)]
 #![feature(async_iterator)]
 #![feature(bigint_helper_methods)]
+#![feature(bstr)]
 #![feature(cell_update)]
 #![feature(clone_to_uninit)]
 #![feature(const_black_box)]
@@ -139,6 +140,7 @@ mod asserting;
 mod async_iter;
 mod atomic;
 mod bool;
+mod bstr;
 mod cell;
 mod char;
 mod clone;
diff --git a/library/core/tests/macros.rs b/library/coretests/tests/macros.rs
similarity index 100%
rename from library/core/tests/macros.rs
rename to library/coretests/tests/macros.rs
diff --git a/library/core/tests/macros_bootstrap.rs b/library/coretests/tests/macros_bootstrap.rs
similarity index 100%
rename from library/core/tests/macros_bootstrap.rs
rename to library/coretests/tests/macros_bootstrap.rs
diff --git a/library/core/tests/manually_drop.rs b/library/coretests/tests/manually_drop.rs
similarity index 100%
rename from library/core/tests/manually_drop.rs
rename to library/coretests/tests/manually_drop.rs
diff --git a/library/core/tests/mem.rs b/library/coretests/tests/mem.rs
similarity index 100%
rename from library/core/tests/mem.rs
rename to library/coretests/tests/mem.rs
diff --git a/library/core/tests/net/ip_addr.rs b/library/coretests/tests/net/ip_addr.rs
similarity index 100%
rename from library/core/tests/net/ip_addr.rs
rename to library/coretests/tests/net/ip_addr.rs
diff --git a/library/core/tests/net/mod.rs b/library/coretests/tests/net/mod.rs
similarity index 100%
rename from library/core/tests/net/mod.rs
rename to library/coretests/tests/net/mod.rs
diff --git a/library/core/tests/net/parser.rs b/library/coretests/tests/net/parser.rs
similarity index 100%
rename from library/core/tests/net/parser.rs
rename to library/coretests/tests/net/parser.rs
diff --git a/library/core/tests/net/socket_addr.rs b/library/coretests/tests/net/socket_addr.rs
similarity index 100%
rename from library/core/tests/net/socket_addr.rs
rename to library/coretests/tests/net/socket_addr.rs
diff --git a/library/core/tests/nonzero.rs b/library/coretests/tests/nonzero.rs
similarity index 100%
rename from library/core/tests/nonzero.rs
rename to library/coretests/tests/nonzero.rs
diff --git a/library/core/tests/num/bignum.rs b/library/coretests/tests/num/bignum.rs
similarity index 100%
rename from library/core/tests/num/bignum.rs
rename to library/coretests/tests/num/bignum.rs
diff --git a/library/core/tests/num/const_from.rs b/library/coretests/tests/num/const_from.rs
similarity index 100%
rename from library/core/tests/num/const_from.rs
rename to library/coretests/tests/num/const_from.rs
diff --git a/library/core/tests/num/dec2flt/float.rs b/library/coretests/tests/num/dec2flt/float.rs
similarity index 100%
rename from library/core/tests/num/dec2flt/float.rs
rename to library/coretests/tests/num/dec2flt/float.rs
diff --git a/library/core/tests/num/dec2flt/lemire.rs b/library/coretests/tests/num/dec2flt/lemire.rs
similarity index 100%
rename from library/core/tests/num/dec2flt/lemire.rs
rename to library/coretests/tests/num/dec2flt/lemire.rs
diff --git a/library/core/tests/num/dec2flt/mod.rs b/library/coretests/tests/num/dec2flt/mod.rs
similarity index 100%
rename from library/core/tests/num/dec2flt/mod.rs
rename to library/coretests/tests/num/dec2flt/mod.rs
diff --git a/library/core/tests/num/dec2flt/parse.rs b/library/coretests/tests/num/dec2flt/parse.rs
similarity index 100%
rename from library/core/tests/num/dec2flt/parse.rs
rename to library/coretests/tests/num/dec2flt/parse.rs
diff --git a/library/core/tests/num/float_iter_sum_identity.rs b/library/coretests/tests/num/float_iter_sum_identity.rs
similarity index 100%
rename from library/core/tests/num/float_iter_sum_identity.rs
rename to library/coretests/tests/num/float_iter_sum_identity.rs
diff --git a/library/core/tests/num/flt2dec/estimator.rs b/library/coretests/tests/num/flt2dec/estimator.rs
similarity index 100%
rename from library/core/tests/num/flt2dec/estimator.rs
rename to library/coretests/tests/num/flt2dec/estimator.rs
diff --git a/library/core/tests/num/flt2dec/mod.rs b/library/coretests/tests/num/flt2dec/mod.rs
similarity index 100%
rename from library/core/tests/num/flt2dec/mod.rs
rename to library/coretests/tests/num/flt2dec/mod.rs
diff --git a/library/core/tests/num/flt2dec/random.rs b/library/coretests/tests/num/flt2dec/random.rs
similarity index 100%
rename from library/core/tests/num/flt2dec/random.rs
rename to library/coretests/tests/num/flt2dec/random.rs
diff --git a/library/core/tests/num/flt2dec/strategy/dragon.rs b/library/coretests/tests/num/flt2dec/strategy/dragon.rs
similarity index 100%
rename from library/core/tests/num/flt2dec/strategy/dragon.rs
rename to library/coretests/tests/num/flt2dec/strategy/dragon.rs
diff --git a/library/core/tests/num/flt2dec/strategy/grisu.rs b/library/coretests/tests/num/flt2dec/strategy/grisu.rs
similarity index 100%
rename from library/core/tests/num/flt2dec/strategy/grisu.rs
rename to library/coretests/tests/num/flt2dec/strategy/grisu.rs
diff --git a/library/core/tests/num/i128.rs b/library/coretests/tests/num/i128.rs
similarity index 100%
rename from library/core/tests/num/i128.rs
rename to library/coretests/tests/num/i128.rs
diff --git a/library/core/tests/num/i16.rs b/library/coretests/tests/num/i16.rs
similarity index 100%
rename from library/core/tests/num/i16.rs
rename to library/coretests/tests/num/i16.rs
diff --git a/library/core/tests/num/i32.rs b/library/coretests/tests/num/i32.rs
similarity index 100%
rename from library/core/tests/num/i32.rs
rename to library/coretests/tests/num/i32.rs
diff --git a/library/core/tests/num/i64.rs b/library/coretests/tests/num/i64.rs
similarity index 100%
rename from library/core/tests/num/i64.rs
rename to library/coretests/tests/num/i64.rs
diff --git a/library/core/tests/num/i8.rs b/library/coretests/tests/num/i8.rs
similarity index 100%
rename from library/core/tests/num/i8.rs
rename to library/coretests/tests/num/i8.rs
diff --git a/library/core/tests/num/ieee754.rs b/library/coretests/tests/num/ieee754.rs
similarity index 100%
rename from library/core/tests/num/ieee754.rs
rename to library/coretests/tests/num/ieee754.rs
diff --git a/library/core/tests/num/int_log.rs b/library/coretests/tests/num/int_log.rs
similarity index 100%
rename from library/core/tests/num/int_log.rs
rename to library/coretests/tests/num/int_log.rs
diff --git a/library/core/tests/num/int_macros.rs b/library/coretests/tests/num/int_macros.rs
similarity index 100%
rename from library/core/tests/num/int_macros.rs
rename to library/coretests/tests/num/int_macros.rs
diff --git a/library/core/tests/num/int_sqrt.rs b/library/coretests/tests/num/int_sqrt.rs
similarity index 100%
rename from library/core/tests/num/int_sqrt.rs
rename to library/coretests/tests/num/int_sqrt.rs
diff --git a/library/core/tests/num/midpoint.rs b/library/coretests/tests/num/midpoint.rs
similarity index 100%
rename from library/core/tests/num/midpoint.rs
rename to library/coretests/tests/num/midpoint.rs
diff --git a/library/core/tests/num/mod.rs b/library/coretests/tests/num/mod.rs
similarity index 100%
rename from library/core/tests/num/mod.rs
rename to library/coretests/tests/num/mod.rs
diff --git a/library/core/tests/num/nan.rs b/library/coretests/tests/num/nan.rs
similarity index 100%
rename from library/core/tests/num/nan.rs
rename to library/coretests/tests/num/nan.rs
diff --git a/library/core/tests/num/ops.rs b/library/coretests/tests/num/ops.rs
similarity index 100%
rename from library/core/tests/num/ops.rs
rename to library/coretests/tests/num/ops.rs
diff --git a/library/core/tests/num/u128.rs b/library/coretests/tests/num/u128.rs
similarity index 100%
rename from library/core/tests/num/u128.rs
rename to library/coretests/tests/num/u128.rs
diff --git a/library/core/tests/num/u16.rs b/library/coretests/tests/num/u16.rs
similarity index 100%
rename from library/core/tests/num/u16.rs
rename to library/coretests/tests/num/u16.rs
diff --git a/library/core/tests/num/u32.rs b/library/coretests/tests/num/u32.rs
similarity index 100%
rename from library/core/tests/num/u32.rs
rename to library/coretests/tests/num/u32.rs
diff --git a/library/core/tests/num/u64.rs b/library/coretests/tests/num/u64.rs
similarity index 100%
rename from library/core/tests/num/u64.rs
rename to library/coretests/tests/num/u64.rs
diff --git a/library/core/tests/num/u8.rs b/library/coretests/tests/num/u8.rs
similarity index 100%
rename from library/core/tests/num/u8.rs
rename to library/coretests/tests/num/u8.rs
diff --git a/library/core/tests/num/uint_macros.rs b/library/coretests/tests/num/uint_macros.rs
similarity index 100%
rename from library/core/tests/num/uint_macros.rs
rename to library/coretests/tests/num/uint_macros.rs
diff --git a/library/core/tests/num/wrapping.rs b/library/coretests/tests/num/wrapping.rs
similarity index 100%
rename from library/core/tests/num/wrapping.rs
rename to library/coretests/tests/num/wrapping.rs
diff --git a/library/core/tests/ops.rs b/library/coretests/tests/ops.rs
similarity index 100%
rename from library/core/tests/ops.rs
rename to library/coretests/tests/ops.rs
diff --git a/library/core/tests/ops/control_flow.rs b/library/coretests/tests/ops/control_flow.rs
similarity index 100%
rename from library/core/tests/ops/control_flow.rs
rename to library/coretests/tests/ops/control_flow.rs
diff --git a/library/core/tests/ops/from_residual.rs b/library/coretests/tests/ops/from_residual.rs
similarity index 100%
rename from library/core/tests/ops/from_residual.rs
rename to library/coretests/tests/ops/from_residual.rs
diff --git a/library/core/tests/option.rs b/library/coretests/tests/option.rs
similarity index 100%
rename from library/core/tests/option.rs
rename to library/coretests/tests/option.rs
diff --git a/library/core/tests/panic.rs b/library/coretests/tests/panic.rs
similarity index 100%
rename from library/core/tests/panic.rs
rename to library/coretests/tests/panic.rs
diff --git a/library/core/tests/panic/location.rs b/library/coretests/tests/panic/location.rs
similarity index 100%
rename from library/core/tests/panic/location.rs
rename to library/coretests/tests/panic/location.rs
diff --git a/library/core/tests/pattern.rs b/library/coretests/tests/pattern.rs
similarity index 100%
rename from library/core/tests/pattern.rs
rename to library/coretests/tests/pattern.rs
diff --git a/library/core/tests/pin.rs b/library/coretests/tests/pin.rs
similarity index 100%
rename from library/core/tests/pin.rs
rename to library/coretests/tests/pin.rs
diff --git a/library/core/tests/pin_macro.rs b/library/coretests/tests/pin_macro.rs
similarity index 100%
rename from library/core/tests/pin_macro.rs
rename to library/coretests/tests/pin_macro.rs
diff --git a/library/core/tests/ptr.rs b/library/coretests/tests/ptr.rs
similarity index 100%
rename from library/core/tests/ptr.rs
rename to library/coretests/tests/ptr.rs
diff --git a/library/core/tests/result.rs b/library/coretests/tests/result.rs
similarity index 100%
rename from library/core/tests/result.rs
rename to library/coretests/tests/result.rs
diff --git a/library/core/tests/simd.rs b/library/coretests/tests/simd.rs
similarity index 100%
rename from library/core/tests/simd.rs
rename to library/coretests/tests/simd.rs
diff --git a/library/core/tests/slice.rs b/library/coretests/tests/slice.rs
similarity index 100%
rename from library/core/tests/slice.rs
rename to library/coretests/tests/slice.rs
diff --git a/library/core/tests/str.rs b/library/coretests/tests/str.rs
similarity index 100%
rename from library/core/tests/str.rs
rename to library/coretests/tests/str.rs
diff --git a/library/core/tests/str_lossy.rs b/library/coretests/tests/str_lossy.rs
similarity index 100%
rename from library/core/tests/str_lossy.rs
rename to library/coretests/tests/str_lossy.rs
diff --git a/library/core/tests/task.rs b/library/coretests/tests/task.rs
similarity index 100%
rename from library/core/tests/task.rs
rename to library/coretests/tests/task.rs
diff --git a/library/core/tests/time.rs b/library/coretests/tests/time.rs
similarity index 100%
rename from library/core/tests/time.rs
rename to library/coretests/tests/time.rs
diff --git a/library/core/tests/tuple.rs b/library/coretests/tests/tuple.rs
similarity index 100%
rename from library/core/tests/tuple.rs
rename to library/coretests/tests/tuple.rs
diff --git a/library/core/tests/unicode.rs b/library/coretests/tests/unicode.rs
similarity index 100%
rename from library/core/tests/unicode.rs
rename to library/coretests/tests/unicode.rs
diff --git a/library/core/tests/waker.rs b/library/coretests/tests/waker.rs
similarity index 100%
rename from library/core/tests/waker.rs
rename to library/coretests/tests/waker.rs
diff --git a/src/bootstrap/mk/Makefile.in b/src/bootstrap/mk/Makefile.in
index 275c0e803cb61..7e6a39a236e07 100644
--- a/src/bootstrap/mk/Makefile.in
+++ b/src/bootstrap/mk/Makefile.in
@@ -55,14 +55,14 @@ check-aux:
 		$(BOOTSTRAP_ARGS)
 	# Run standard library tests in Miri.
 	$(Q)$(BOOTSTRAP) miri --stage 2 \
-		library/core \
+		library/coretests \
 		library/alloc \
 		$(BOOTSTRAP_ARGS) \
 		--no-doc
 	# Some doctests use file system operations to demonstrate dealing with `Result`.
 	$(Q)MIRIFLAGS="-Zmiri-disable-isolation" \
 		$(BOOTSTRAP) miri --stage 2 \
-		library/core \
+		library/coretests \
 		library/alloc \
 		$(BOOTSTRAP_ARGS) \
 		--doc
diff --git a/src/bootstrap/src/core/build_steps/check.rs b/src/bootstrap/src/core/build_steps/check.rs
index d8d862caf6a9a..f4a86e263967d 100644
--- a/src/bootstrap/src/core/build_steps/check.rs
+++ b/src/bootstrap/src/core/build_steps/check.rs
@@ -45,7 +45,7 @@ impl Step for Std {
     const DEFAULT: bool = true;
 
     fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
-        run.crate_or_deps("sysroot").path("library")
+        run.crate_or_deps("sysroot").crate_or_deps("coretests").path("library")
     }
 
     fn make_run(run: RunConfig<'_>) {
diff --git a/src/bootstrap/src/core/build_steps/test.rs b/src/bootstrap/src/core/build_steps/test.rs
index 99b033db115ce..5e250d18ce6aa 100644
--- a/src/bootstrap/src/core/build_steps/test.rs
+++ b/src/bootstrap/src/core/build_steps/test.rs
@@ -2658,7 +2658,7 @@ impl Step for Crate {
     const DEFAULT: bool = true;
 
     fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
-        run.crate_or_deps("sysroot")
+        run.crate_or_deps("sysroot").crate_or_deps("coretests")
     }
 
     fn make_run(run: RunConfig<'_>) {