refactor(@angular/build): decouple test discovery from runner execution

packages/angular/build/src/builders/unit-test/builder.ts

@@ -144,9 +144,8 @@ export async function* execute(
   const normalizedOptions = await normalizeOptions(context, projectName, options);
   const runner = await loadTestRunner(normalizedOptions.runnerName);
 
-  await using executor = await runner.createExecutor(context, normalizedOptions);
-
   if (runner.isStandalone) {
+    await using executor = await runner.createExecutor(context, normalizedOptions, undefined);
     yield* executor.execute({
       kind: ResultKind.Full,
       files: {},
@@ -174,9 +173,16 @@ export async function* execute(
   }
 
   // Get runner-specific build options from the hook
-  const { buildOptions: runnerBuildOptions, virtualFiles } = await runner.getBuildOptions(
+  const {
+    buildOptions: runnerBuildOptions,
+    virtualFiles,
+    testEntryPointMappings,
+  } = await runner.getBuildOptions(normalizedOptions, buildTargetOptions);
+
+  await using executor = await runner.createExecutor(
+    context,
     normalizedOptions,
-    buildTargetOptions,
+    testEntryPointMappings,
   );
 
   const finalExtensions = prepareBuildExtensions(

packages/angular/build/src/builders/unit-test/runners/api.ts

@@ -11,9 +11,27 @@ import type { ApplicationBuilderInternalOptions } from '../../application/option
 import type { FullResult, IncrementalResult } from '../../application/results';
 import type { NormalizedUnitTestBuilderOptions } from '../options';
 
+/**
+ * Represents the options for a test runner.
+ */
 export interface RunnerOptions {
+  /**
+   * Partial options for the application builder.
+   * These will be merged with the options from the build target.
+   */
   buildOptions: Partial<ApplicationBuilderInternalOptions>;
+
+  /**
+   * A record of virtual files to be added to the build.
+   * The key is the file path and the value is the file content.
+   */
   virtualFiles?: Record<string, string>;
+
+  /**
+   * A map of test entry points to their corresponding test files.
+   * This is used to avoid re-discovering the test files in the executor.
+   */
+  testEntryPointMappings?: Map<string, string>;
 }
 
 /**
@@ -51,10 +69,12 @@ export interface TestRunner {
    *
    * @param context The Architect builder context.
    * @param options The normalized unit test options.
+   * @param testEntryPointMappings A map of test entry points to their corresponding test files.
    * @returns A TestExecutor instance that will handle the test runs.
    */
   createExecutor(
     context: BuilderContext,
     options: NormalizedUnitTestBuilderOptions,
+    testEntryPointMappings: Map<string, string> | undefined,
   ): Promise<TestExecutor>;
 }

packages/angular/build/src/builders/unit-test/runners/vitest/build-options.ts

@@ -120,5 +120,6 @@ export async function getVitestBuildOptions(
     virtualFiles: {
       'angular:test-bed-init': testBedInitContents,
     },
+    testEntryPointMappings: entryPoints,
   };
 }

packages/angular/build/src/builders/unit-test/runners/vitest/executor.ts

@@ -40,9 +40,20 @@ export class VitestExecutor implements TestExecutor {
   private readonly testFileToEntryPoint = new Map<string, string>();
   private readonly entryPointToTestFile = new Map<string, string>();
 
-  constructor(projectName: string, options: NormalizedUnitTestBuilderOptions) {
+  constructor(
+    projectName: string,
+    options: NormalizedUnitTestBuilderOptions,
+    testEntryPointMappings: Map<string, string> | undefined,
+  ) {
     this.projectName = projectName;
     this.options = options;
+
+    if (testEntryPointMappings) {
+      for (const [entryPoint, testFile] of testEntryPointMappings) {
+        this.testFileToEntryPoint.set(testFile, entryPoint);
+        this.entryPointToTestFile.set(entryPoint + '.js', testFile);
+      }
+    }
   }
 
   async *execute(buildResult: FullResult | IncrementalResult): AsyncIterable<BuilderOutput> {
@@ -60,25 +71,6 @@ export class VitestExecutor implements TestExecutor {
       }
     }
 
-    // The `getTestEntrypoints` function is used here to create the same mapping
-    // that was used in `build-options.ts` to generate the build entry points.
-    // This is a deliberate duplication to avoid a larger refactoring of the
-    // builder's core interfaces to pass the entry points from the build setup
-    // phase to the execution phase.
-    if (this.testFileToEntryPoint.size === 0) {
-      const { include, exclude = [], workspaceRoot, projectSourceRoot } = this.options;
-      const testFiles = await findTests(include, exclude, workspaceRoot, projectSourceRoot);
-      const entryPoints = getTestEntrypoints(testFiles, {
-        projectSourceRoot,
-        workspaceRoot,
-        removeTestExtension: true,
-      });
-      for (const [entryPoint, testFile] of entryPoints) {
-        this.testFileToEntryPoint.set(testFile, entryPoint);
-        this.entryPointToTestFile.set(entryPoint + '.js', testFile);
-      }
-    }
-
     // Initialize Vitest if not already present.
     this.vitest ??= await this.initializeVitest();
     const vitest = this.vitest;

packages/angular/build/src/builders/unit-test/runners/vitest/index.ts

@@ -21,11 +21,11 @@ const VitestTestRunner: TestRunner = {
     return getVitestBuildOptions(options, baseBuildOptions);
   },
 
-  async createExecutor(context, options) {
+  async createExecutor(context, options, testEntryPointMappings) {
     const projectName = context.target?.project;
     assert(projectName, 'The builder requires a target.');
 
-    return new VitestExecutor(projectName, options);
+    return new VitestExecutor(projectName, options, testEntryPointMappings);
   },
 };