Add end-to-end tests for command-line interface

.github/workflows/ci.yml

@@ -25,8 +25,12 @@ jobs:
           key: ${{ runner.os }}-spm-xcode-${{ matrix.xcode }}-${{ hashFiles('**/Package.resolved') }}
           restore-keys: |
             ${{ runner.os }}-spm-xcode-${{ matrix.xcode }}-
+      - name: Install System Dependencies
+        run: |
+          brew install graphviz
       - name: Build and Test
-        run: swift test -c release
+        run: |
+          swift test -c release
         env:
           DEVELOPER_DIR: /Applications/Xcode_${{ matrix.xcode }}.app/Contents/Developer
 
@@ -52,6 +56,6 @@ jobs:
       - name: Install System Dependencies
         run: |
           apt-get update
-          apt-get install -y libxml2-dev
+          apt-get install -y libxml2-dev graphviz
       - name: Build and Test
         run: swift test -c release --enable-test-discovery

Changelog.md

@@ -7,6 +7,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+
+- Added an end-to-end test for validity of generated `all.css` file.
+  #199 by @MaxDesiatov.
+
 ## [1.0.0-beta.5] - 2020-09-29
 
 ### Added

Package.swift

@@ -63,5 +63,11 @@ let package = Package(
                 .product(name: "SwiftMarkup", package: "SwiftMarkup")
             ]
         ),
+        .testTarget(
+            name: "EndToEndTests",
+            dependencies: [
+                .target(name: "swift-doc"),
+            ]
+        ),
     ]
 )

Package@swift-5.2.swift

@@ -41,5 +41,11 @@ let package = Package(
             name: "SwiftDocTests",
             dependencies: ["SwiftDoc", "SwiftSyntax", "SwiftSemantics", "SwiftMarkup"]
         ),
+        .testTarget(
+            name: "EndToEndTests",
+            dependencies: [
+                .target(name: "swift-doc"),
+            ]
+        ),
     ]
 )

Tests/EndToEndTests/EndToEndTests.swift

@@ -0,0 +1,50 @@
+import class Foundation.Bundle
+import XCTest
+
+final class EndToEndTests: XCTestCase {
+  func testCSS() throws {
+    // Some of the APIs that we use below are available in macOS 10.13 and above.
+    let process = Process()
+    process.executableURL = productsDirectory.appendingPathComponent("swift-doc")
+    process.arguments = ["generate", "--module-name", "SwiftDoc", "--format", "html", "Sources"]
+
+    let pipe = Pipe()
+    process.standardOutput = pipe
+
+    if #available(OSX 10.13, *) {
+      try process.run()
+    } else {
+      process.launch()
+    }
+    process.waitUntilExit()
+
+    let data = pipe.fileHandleForReading.readDataToEndOfFile()
+    let output = String(data: data, encoding: .utf8)
+
+    XCTAssertEqual(output, "")
+
+    let cssPath = productsDirectory
+      .deletingLastPathComponent()
+      .deletingLastPathComponent()
+      .appendingPathComponent("documentation")
+      .appendingPathComponent("all.css")
+    let cssData = try Data(contentsOf: cssPath)
+    guard let css = String(data: cssData, encoding: .utf8) else {
+      return XCTFail("Failed to decode a UTF-8 string from `cssData` in \(#function)")
+    }
+
+    XCTAssertTrue(css.contains(":root"))
+  }
+
+  /// Returns path to the built products directory.
+  lazy var productsDirectory: URL = {
+    #if os(macOS)
+    for bundle in Bundle.allBundles where bundle.bundlePath.hasSuffix(".xctest") {
+      return bundle.bundleURL.deletingLastPathComponent()
+    }
+    fatalError("couldn't find the products directory")
+    #else
+    return Bundle.main.bundleURL
+    #endif
+  }()
+}