Prepend module name to TestItem IDs

It is possible to have two identically named suites in two different
test targets. These were being erroniously rolled up in to the same
parent TestItem.

Disambiguate these TestItems by prepending the module name. This has the
added benefit of making the TestItem IDs a fully qualified name that can
be passed to `swift test`.

The module name is pulled from the compiler arguments for the target. If
no module name can be found we fall back to the `targetID` for the
`ConfiguredTarget`.

Author: plemarquand

Sources/SKCore/BuildSystemManager.swift

@@ -154,6 +154,18 @@ extension BuildSystemManager {
       .first
   }
 
+  /// Returns the target's module name as parsed from the `ConfiguredTarget`'s compiler arguments.
+  public func moduleName(for document: DocumentURI, in target: ConfiguredTarget) async -> String? {
+    guard let buildSettings = await buildSettings(for: document, in: target, language: .swift),
+      let moduleNameFlagIndex = buildSettings.compilerArguments.firstIndex(of: "-module-name")
+    else {
+      return nil
+    }
+
+    let moduleNameIndex = buildSettings.compilerArguments.index(after: moduleNameFlagIndex)
+    return buildSettings.compilerArguments[moduleNameIndex]
+  }
+
   /// Returns the build settings for `document` from `buildSystem`.
   ///
   /// Implementation detail of `buildSettings(for:language:)`.

Sources/SourceKitLSP/TestDiscovery.swift

@@ -260,7 +260,7 @@ extension SourceKitLSPServer {
 
   func workspaceTests(_ req: WorkspaceTestsRequest) async throws -> [TestItem] {
     return await self.workspaces
-      .concurrentMap { await self.tests(in: $0) }
+      .concurrentMap { await self.tests(in: $0).prefixTestsWithModuleName(workspace: $0) }
       .flatMap { $0 }
       .sorted { $0.testItem.location < $1.testItem.location }
       .mergingTestsInExtensions()
@@ -272,6 +272,7 @@ extension SourceKitLSPServer {
     languageService: LanguageService
   ) async throws -> [TestItem] {
     return try await documentTestsWithoutMergingExtensions(req, workspace: workspace, languageService: languageService)
+      .prefixTestsWithModuleName(workspace: workspace)
       .mergingTestsInExtensions()
   }
 
@@ -476,6 +477,42 @@ fileprivate extension Array<AnnotatedTestItem> {
     }
     return result
   }
+
+  func prefixTestsWithModuleName(workspace: Workspace) async -> Self {
+    return await self.asyncMap({
+      // If the module name can't be determined we return the test item without a prefixed id.
+      guard let moduleName = await self.moduleName(from: workspace, for: $0.testItem.location.uri) else {
+        return $0
+      }
+      var newTest = $0.testItem
+      newTest.id = "\(moduleName).\(newTest.id)"
+      newTest.children = await prefixTestsWithModuleName(workspace: workspace, newTest.children)
+      return AnnotatedTestItem(testItem: newTest, isExtension: $0.isExtension)
+    })
+  }
+
+  private func prefixTestsWithModuleName(workspace: Workspace, _ tests: [TestItem]) async -> [TestItem] {
+    return await tests.asyncMap({
+      guard let moduleName = await self.moduleName(from: workspace, for: $0.location.uri) else {
+        return $0
+      }
+
+      var newTest = $0
+      newTest.id = "\(moduleName).\(newTest.id)"
+      newTest.children = await prefixTestsWithModuleName(workspace: workspace, newTest.children)
+      return newTest
+    })
+  }
+
+  private func moduleName(from workspace: Workspace, for uri: DocumentURI) async -> String? {
+    guard let configuredTarget = await workspace.buildSystemManager.canonicalConfiguredTarget(for: uri) else {
+      return nil
+    }
+    // If for whatever reason we can't get a module name from the build system, fall back
+    // to using the targetID as this would be used when there is no command line arguments
+    // to define the module name as something other than the targetID.
+    return await workspace.buildSystemManager.moduleName(for: uri, in: configuredTarget) ?? configuredTarget.targetID
+  }
 }
 
 extension SwiftLanguageService {