angular-testing

Test signal components by setting inputs with fixture.componentRef.setInput and mutating signals directly via .set() or .update(). Call fixture.detectChanges() after changes, then assert on computed values or rendered DOM output.

Install vitest and jsdom, then update angular.json to use the @angular/build:unit-test builder with your tsconfig.spec.json including vitest/globals types. Run tests with ng test, with optional --watch and --code-coverage flags.

Vitest offers faster execution with native ESM, instant watch feedback, and a built-in UI mode, while Jasmine with Karma is the traditional default. Angular v20+ supports Vitest natively, and migration maps jasmine.createSpy to vi.fn and spyOn to vi.spyOn.

Provide provideHttpClient and provideHttpClientTesting in TestBed, inject HttpTestingController, then use expectOne to match the request URL and flush mock response data. Call httpMock.verify() in afterEach to ensure no outstanding requests remain.

OnPush components require explicit change detection in tests. Set signal inputs with fixture.componentRef.setInput and call fixture.detectChanges() after each update so the template re-renders with the new values.

Yes, use RouterTestingHarness with provideRouter to navigate by URL and assert on the activated component. For guards, mock the authentication service and verify that navigation succeeds or redirects based on the guard result.