fix(@angular/build): only require karma-coverage when coverage is enabled

The upfront dependency validation of the unit-test builder's karma runner checks
the truthiness of the normalized `coverage` option, which is always an object
since the introduction of the advanced coverage options. As a result, `ng test`
with the karma runner fails with a `MissingDependenciesError` requesting the
`karma-coverage` package even when coverage is disabled. Check the `enabled`
property instead, matching the vitest runner and the karma executor. A new unit
spec for the karma runner's dependency validation fails without this change.

Author: MeAkib

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

@@ -30,7 +30,7 @@ const KarmaTestRunner: TestRunner = {
       }
     }
 
-    if (options.coverage) {
+    if (options.coverage.enabled) {
       checker.check('karma-coverage');
     }
 

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

@@ -0,0 +1,56 @@
+/**
+ * @license
+ * Copyright Google LLC All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.dev/license
+ */
+
+import assert from 'node:assert';
+import { mkdir, mkdtemp, writeFile } from 'node:fs/promises';
+import { join } from 'node:path';
+import type { NormalizedUnitTestBuilderOptions } from '../../options';
+import KarmaTestRunner from './index';
+
+describe('KarmaTestRunner', () => {
+  describe('validateDependencies', () => {
+    let projectSourceRoot: string;
+
+    function createOptions(coverageEnabled: boolean): NormalizedUnitTestBuilderOptions {
+      return {
+        projectSourceRoot,
+        coverage: { enabled: coverageEnabled },
+      } as NormalizedUnitTestBuilderOptions;
+    }
+
+    beforeAll(async () => {
+      const baseTmpDir = process.env['TEST_TMPDIR'];
+      assert(baseTmpDir, 'TEST_TMPDIR is not set');
+      projectSourceRoot = await mkdtemp(join(baseTmpDir, 'angular-cli-karma-runner-'));
+
+      // A project with karma and karma-jasmine installed but not karma-coverage
+      await writeFile(join(projectSourceRoot, 'package.json'), '{"name": "test-project"}');
+      for (const packageName of ['karma', 'karma-jasmine']) {
+        const packageRoot = join(projectSourceRoot, 'node_modules', packageName);
+        await mkdir(packageRoot, { recursive: true });
+        await writeFile(
+          join(packageRoot, 'package.json'),
+          JSON.stringify({ name: packageName, version: '0.0.0', main: 'index.js' }),
+        );
+        await writeFile(join(packageRoot, 'index.js'), '');
+      }
+    });
+
+    it('does not require karma-coverage when coverage is disabled', async () => {
+      await expectAsync(
+        Promise.resolve().then(() => KarmaTestRunner.validateDependencies?.(createOptions(false))),
+      ).toBeResolved();
+    });
+
+    it('requires karma-coverage when coverage is enabled', async () => {
+      await expectAsync(
+        Promise.resolve().then(() => KarmaTestRunner.validateDependencies?.(createOptions(true))),
+      ).toBeRejectedWithError(/karma-coverage/);
+    });
+  });
+});