fix(@angular/build): warn about unsupported options in the unit-test karma runner

The karma runner silently ignored `providersFile`, `outputFile` and `coverageReporters`.
For example, `ng test --runner karma --coverage --coverage-reporters lcov` wrote no `lcov.info`
and printed nothing. Log the same "not supported" warning that the runner already logs for its
other unsupported options.

Author: MeAkib

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

@@ -53,6 +53,24 @@ export class KarmaExecutor implements TestExecutor {
       );
     }
 
+    if (unitTestOptions.providersFile) {
+      context.logger.warn(
+        'The "karma" test runner does not support the "providersFile" option. The option will be ignored.',
+      );
+    }
+
+    if (unitTestOptions.outputFile) {
+      context.logger.warn(
+        'The "karma" test runner does not support the "outputFile" option. The option will be ignored.',
+      );
+    }
+
+    if (unitTestOptions.coverage.reporters) {
+      context.logger.warn(
+        'The "karma" test runner does not support the "coverageReporters" option. The option will be ignored.',
+      );
+    }
+
     const buildTargetOptions = (await context.validateOptions(
       await context.getTargetOptions(unitTestOptions.buildTarget),
       await context.getBuilderNameForTarget(unitTestOptions.buildTarget),

packages/angular/build/src/builders/unit-test/runners/karma/executor_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 type { BuilderContext } from '@angular-devkit/architect';
+import type { NormalizedUnitTestBuilderOptions } from '../../options';
+import { KarmaExecutor } from './executor';
+
+describe('KarmaExecutor', () => {
+  async function getWarnings(options: Record<string, unknown>): Promise<string[]> {
+    const warn = jasmine.createSpy('warn');
+    // The unsupported option warnings are logged before the build target is read, so stop there.
+    const context = {
+      logger: { warn },
+      getTargetOptions: () => Promise.reject(new Error('stop')),
+    } as unknown as BuilderContext;
+
+    const executor = new KarmaExecutor(context, {
+      setupFiles: [],
+      coverage: { enabled: false },
+      ...options,
+    } as unknown as NormalizedUnitTestBuilderOptions);
+
+    await expectAsync(executor.execute()[Symbol.asyncIterator]().next()).toBeRejectedWithError(
+      'stop',
+    );
+
+    return warn.calls.allArgs().map(([message]) => message);
+  }
+
+  it('warns that the "providersFile" option is not supported', async () => {
+    expect(await getWarnings({ providersFile: '/src/test-providers.ts' })).toContain(
+      'The "karma" test runner does not support the "providersFile" option. The option will be ignored.',
+    );
+  });
+
+  it('warns that the "outputFile" option is not supported', async () => {
+    expect(await getWarnings({ outputFile: 'test-results.xml' })).toContain(
+      'The "karma" test runner does not support the "outputFile" option. The option will be ignored.',
+    );
+  });
+
+  it('warns that the "coverageReporters" option is not supported', async () => {
+    expect(await getWarnings({ coverage: { enabled: true, reporters: [['lcov', {}]] } })).toContain(
+      'The "karma" test runner does not support the "coverageReporters" option. The option will be ignored.',
+    );
+  });
+
+  it('does not warn when no unsupported options are set', async () => {
+    expect(await getWarnings({})).toEqual([]);
+  });
+});