Add end-to-end continuous integration tests for Homebrew distribution

.github/workflows/homebrew_ci.yml

@@ -0,0 +1,45 @@
+name: homebrew CI
+
+on:
+  push:
+    branches: [master]
+  schedule:
+    - cron: 0 0 * * *
+
+jobs:
+  homebrew-bottle:
+    runs-on: macos-10.15
+    name: homebrew from bottle
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v1
+      - uses: actions/cache@v2
+        with:
+          path: .build
+          key: ${{ runner.os }}-spm-xcode-${{ matrix.xcode }}-${{ hashFiles('**/Package.resolved') }}
+          restore-keys: |
+            ${{ runner.os }}-spm-xcode-${{ matrix.xcode }}-
+      - name: Install swift-doc
+        run: brew install swiftdocorg/formulae/swift-doc --force-bottle
+      - name: Run Tests
+        run: |
+          swift test --filter EndToEndTests. -Xswiftc -DUSE_HOMEBREW
+
+  homebrew-sources:
+    runs-on: macos-11.0
+
+    name: homebrew from source
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v1
+      - uses: actions/cache@v2
+        with:
+          path: .build
+          key: ${{ runner.os }}-spm-xcode-${{ hashFiles('**/Package.resolved') }}
+          restore-keys: |
+            ${{ runner.os }}-spm-xcode-
+      - name: Install swift-doc
+        run: brew install swiftdocorg/formulae/swift-doc --build-from-source
+      - name: Run Tests
+        run: swift test --filter EndToEndTests. -Xswiftc -DUSE_HOMEBREW

Tests/EndToEndTests/CoverageSubcommandTests.swift

@@ -2,7 +2,7 @@ import XCTest
 
 final class CoverageSubcommandTests: XCTestCase {
     func testStandardOutput() throws {
-        let command = Bundle.productsDirectory.appendingPathComponent("swift-doc")
+        let command = getSwiftDocCommand()
 
         let outputDirectory = try temporaryDirectory()
         defer { try? FileManager.default.removeItem(at: outputDirectory) }
@@ -20,7 +20,7 @@ final class CoverageSubcommandTests: XCTestCase {
     }
 
     func testFileOutput() throws {
-        let command = Bundle.productsDirectory.appendingPathComponent("swift-doc")
+        let command = getSwiftDocCommand()
 
         let outputDirectory = try temporaryDirectory()
         let outputFile = outputDirectory.appendingPathComponent("report.json")

Tests/EndToEndTests/DiagramSubcommandTests.swift

@@ -2,7 +2,7 @@ import XCTest
 
 final class DiagramSubcommandTests: XCTestCase {
     func testStandardOutput() throws {
-        let command = Bundle.productsDirectory.appendingPathComponent("swift-doc")
+        let command = getSwiftDocCommand()
 
         let outputDirectory = try temporaryDirectory()
         defer { try? FileManager.default.removeItem(at: outputDirectory) }

Tests/EndToEndTests/GenerateSubcommandTests.swift

@@ -2,7 +2,7 @@ import XCTest
 
 final class GenerateSubcommandTests: XCTestCase {
     func testCommonMark() throws {
-        let command = Bundle.productsDirectory.appendingPathComponent("swift-doc")
+        let command = getSwiftDocCommand()
 
         let outputDirectory = try temporaryDirectory()
         defer { try? FileManager.default.removeItem(at: outputDirectory) }

Tests/EndToEndTests/Helpers/XCTestCase+Extensions.swift

@@ -0,0 +1,11 @@
+import XCTest
+
+extension XCTestCase {
+    func getSwiftDocCommand() -> URL {
+        #if USE_HOMEBREW
+        return URL(fileURLWithPath: "/usr/local/bin/swift-doc")
+        #else
+        return Bundle.productsDirectory.appendingPathComponent("swift-doc")
+        #endif
+    }
+}