Add standard initialization response for custom build server that supports background indexing

Author: ahoppen

Sources/SKTestSupport/CustomBuildServerTestProject.swift

@@ -161,9 +161,7 @@ package extension CustomBuildServer {
   // MARK: Helper functions for the implementation of BSP methods
 
   func initializationResponse(
-    initializeData: SourceKitInitializeBuildResponseData = SourceKitInitializeBuildResponseData(
-      sourceKitOptionsProvider: true
-    )
+    initializeData: SourceKitInitializeBuildResponseData = .init(sourceKitOptionsProvider: true)
   ) -> InitializeBuildResponse {
     InitializeBuildResponse(
       displayName: "\(type(of: self))",
@@ -175,6 +173,17 @@ package extension CustomBuildServer {
     )
   }
 
+  func initializationResponseSupportingBackgroundIndexing(projectRoot: URL) throws -> InitializeBuildResponse {
+    return initializationResponse(
+      initializeData: SourceKitInitializeBuildResponseData(
+        indexDatabasePath: try projectRoot.appendingPathComponent("index-db").filePath,
+        indexStorePath: try projectRoot.appendingPathComponent("index-store").filePath,
+        prepareProvider: true,
+        sourceKitOptionsProvider: true
+      )
+    )
+  }
+
   func dummyTargetSourcesResponse(_ files: some Sequence<DocumentURI>) -> BuildTargetSourcesResponse {
     return BuildTargetSourcesResponse(items: [
       SourcesItem(target: .dummy, sources: files.map { SourceItem(uri: $0, kind: .file, generated: false) })

Tests/SourceKitLSPTests/BackgroundIndexingTests.swift

@@ -1954,14 +1954,7 @@ final class BackgroundIndexingTests: XCTestCase {
       }
 
       func initializeBuildRequest(_ request: InitializeBuildRequest) async throws -> InitializeBuildResponse {
-        return initializationResponse(
-          initializeData: SourceKitInitializeBuildResponseData(
-            indexDatabasePath: try projectRoot.appendingPathComponent("index-db").filePath,
-            indexStorePath: try projectRoot.appendingPathComponent("index-store").filePath,
-            prepareProvider: true,
-            sourceKitOptionsProvider: true
-          )
-        )
+        return try initializationResponseSupportingBackgroundIndexing(projectRoot: projectRoot)
       }
 
       func buildTargetSourcesRequest(_ request: BuildTargetSourcesRequest) -> BuildTargetSourcesResponse {