fix(@angular/build): correct Vitest coverage reporting for test files

Test coverage reporting within the Vitest runner was inaccurate because the test files themselves were being included in the coverage analysis. This was caused by how the in-memory provider directly loaded the test content.

This commit resolves the issue by introducing an intermediate virtual module for each test. The test entry point now only imports this module, which in turn contains the bundled test code. This extra layer of indirection prevents Vitest from including the test files in the coverage results, leading to an accurate analysis.

To support this change, the `getTestEntrypoints` function now removes the `.spec` or `.test` extension from bundle names, ensuring cleaner module identifiers. The Vitest runner has also been updated to better handle coverage exclusion options and resolve relative paths more reliably.

Author: clydin

packages/angular/build/src/builders/karma/find-tests.ts

@@ -30,12 +30,13 @@ export async function findTests(
 interface TestEntrypointsOptions {
   projectSourceRoot: string;
   workspaceRoot: string;
+  removeTestExtension?: boolean;
 }
 
 /** Generate unique bundle names for a set of test files. */
 export function getTestEntrypoints(
   testFiles: string[],
-  { projectSourceRoot, workspaceRoot }: TestEntrypointsOptions,
+  { projectSourceRoot, workspaceRoot, removeTestExtension }: TestEntrypointsOptions,
 ): Map<string, string> {
   const seen = new Set<string>();
 
@@ -46,7 +47,13 @@ export function getTestEntrypoints(
         .replace(/^[./\\]+/, '')
         // Replace any path separators with dashes.
         .replace(/[/\\]/g, '-');
-      const baseName = `spec-${basename(relativePath, extname(relativePath))}`;
+
+      let fileName = basename(relativePath, extname(relativePath));
+      if (removeTestExtension) {
+        fileName = fileName.replace(/\.(spec|test)$/, '');
+      }
+
+      const baseName = `spec-${fileName}`;
       let uniqueName = baseName;
       let suffix = 2;
       while (seen.has(uniqueName)) {

packages/angular/build/src/builders/karma/find-tests_spec.ts

@@ -62,6 +62,36 @@ describe('getTestEntrypoints', () => {
           ]),
         );
       });
+
+      describe('with removeTestExtension enabled', () => {
+        function getEntrypoints(workspaceRelative: string[], sourceRootRelative: string[] = []) {
+          return getTestEntrypoints(
+            [
+              ...workspaceRelative.map((p) => joinWithSeparator(options.workspaceRoot, p)),
+              ...sourceRootRelative.map((p) => joinWithSeparator(options.projectSourceRoot, p)),
+            ],
+            { ...options, removeTestExtension: true },
+          );
+        }
+
+        it('removes .spec extension', () => {
+          expect(getEntrypoints(['a/b.spec.js'], ['c/d.spec.js'])).toEqual(
+            new Map<string, string>([
+              ['spec-a-b', joinWithSeparator(options.workspaceRoot, 'a/b.spec.js')],
+              ['spec-c-d', joinWithSeparator(options.projectSourceRoot, 'c/d.spec.js')],
+            ]),
+          );
+        });
+
+        it('removes .test extension', () => {
+          expect(getEntrypoints(['a/b.test.js'], ['c/d.test.js'])).toEqual(
+            new Map<string, string>([
+              ['spec-a-b', joinWithSeparator(options.workspaceRoot, 'a/b.test.js')],
+              ['spec-c-d', joinWithSeparator(options.projectSourceRoot, 'c/d.test.js')],
+            ]),
+          );
+        });
+      });
     });
   }
 });

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

@@ -82,7 +82,11 @@ export async function getVitestBuildOptions(
     );
   }
 
-  const entryPoints = getTestEntrypoints(testFiles, { projectSourceRoot, workspaceRoot });
+  const entryPoints = getTestEntrypoints(testFiles, {
+    projectSourceRoot,
+    workspaceRoot,
+    removeTestExtension: true,
+  });
   entryPoints.set('init-testbed', 'angular:test-bed-init');
 
   const buildOptions: Partial<ApplicationBuilderInternalOptions> = {

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

@@ -68,7 +68,11 @@ export class VitestExecutor implements TestExecutor {
     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 });
+      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);
@@ -162,16 +166,15 @@ export class VitestExecutor implements TestExecutor {
                 name: 'angular:test-in-memory-provider',
                 enforce: 'pre',
                 resolveId: (id, importer) => {
-                  if (importer && id.startsWith('.')) {
+                  if (importer && (id[0] === '.' || id[0] === '/')) {
                     let fullPath;
-                    let relativePath;
                     if (this.testFileToEntryPoint.has(importer)) {
                       fullPath = toPosixPath(path.join(this.options.workspaceRoot, id));
-                      relativePath = path.normalize(id);
                     } else {
                       fullPath = toPosixPath(path.join(path.dirname(importer), id));
-                      relativePath = path.relative(this.options.workspaceRoot, fullPath);
                     }
+
+                    const relativePath = path.relative(this.options.workspaceRoot, fullPath);
                     if (this.buildResultFiles.has(toPosixPath(relativePath))) {
                       return fullPath;
                     }
@@ -201,6 +204,12 @@ export class VitestExecutor implements TestExecutor {
                   let outputPath;
                   if (entryPoint) {
                     outputPath = entryPoint + '.js';
+
+                    // To support coverage exclusion of the actual test file, the virtual
+                    // test entry point only references the built and bundled intermediate file.
+                    return {
+                      code: `import "./${outputPath}";`,
+                    };
                   } else {
                     // Attempt to load as a built artifact.
                     const relativePath = path.relative(this.options.workspaceRoot, id);
@@ -247,15 +256,6 @@ export class VitestExecutor implements TestExecutor {
               },
             ],
           });
-
-          // Adjust coverage excludes to not include the otherwise automatically inserted included unit tests.
-          // Vite does this as a convenience but is problematic for the bundling strategy employed by the
-          // builder's test setup. To workaround this, the excludes are adjusted here to only automatically
-          // exclude the TypeScript source test files.
-          project.config.coverage.exclude = [
-            ...(codeCoverage?.exclude ?? []),
-            '**/*.{test,spec}.?(c|m)ts',
-          ];
         },
       },
     ];
@@ -343,7 +343,8 @@ function generateCoverageOption(
   return {
     enabled: true,
     excludeAfterRemap: true,
-    // Special handling for `reporter` due to an undefined value causing upstream failures
+    // Special handling for `exclude`/`reporters` due to an undefined value causing upstream failures
+    ...(codeCoverage.exclude ? { exclude: codeCoverage.exclude } : {}),
     ...(codeCoverage.reporters
       ? ({ reporter: codeCoverage.reporters } satisfies VitestCoverageOption)
       : {}),

packages/angular/build/src/builders/unit-test/schema.json

@@ -60,8 +60,7 @@
       "description": "Globs to exclude from code coverage.",
       "items": {
         "type": "string"
-      },
-      "default": []
+      }
     },
     "codeCoverageReporters": {
       "type": "array",