Mock components, services, and more to simplify Angular testing

ng-mocks is a testing library that helps with mocking services, components, directives, pipes and modules in tests for Angular applications. When you have a noisy child component, or any other annoying dependency, ng-mocks has tools to turn these declarations into their mocks, keeping interfaces as they are, but suppressing their implementation.

The current version of ng-mocks has been tested and can be used with:

angular	ng-mocks	jasmine	jest	ivy	standalone	signals	defer
22	latest	yes	yes	yes	yes	yes	no
21	latest	yes	yes	yes	yes	yes	no
20	latest	yes	yes	yes	yes	yes	no
19	latest	yes	yes	yes	yes	yes	no
18	latest	yes	yes	yes	yes	yes	no
17	latest	yes	yes	yes	yes	yes	no
16	latest	yes	yes	yes	yes	yes
15	latest	yes	yes	yes	yes
14	latest	yes	yes	yes	yes
13	latest	yes	yes	yes
12	latest	yes	yes	yes
11	latest	yes	yes	yes
10	latest	yes	yes	yes
9	latest	yes	yes	yes
8	latest	yes	yes
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6	latest	yes	yes
5	latest	yes	yes

The header menu contains preconfigured sandboxes, where you can explore the features. To focus on a particular one, simply prefix it with fdescribe or fit.

There is also a brief summary of the latest changes in CHANGELOG.

Very short introduction

Put the global configuration for mocks in src/test.ts. For Jest, use src/setup-jest.ts / src/test-setup.ts.

src/test.ts
// All methods in mock declarations and providers
// will be automatically spied on their creation.
// https://ng-mocks.sudo.eu/extra/auto-spy
ngMocks.autoSpy('jasmine');
// for Jest: ngMocks.autoSpy('jest')

// ngMocks.defaultMock helps to customize mocks
// globally. Therefore, we can avoid copy-pasting
// among tests.
// https://ng-mocks.sudo.eu/api/ngMocks/defaultMock
ngMocks.defaultMock(AuthService, () => ({
  isLoggedIn$: EMPTY,
  currentUser$: EMPTY,
}));

An example of a spec for a profile edit component.

src/profile.component.spec.ts
// Let's imagine that there is a ProfileComponent
// and it has 3 text fields: email, firstName,
// lastName, and a user can edit them.
// In the following test suite, we would like to
// cover the behavior of the component.
describe('profile:builder', () => {
  // Helps to reset customizations after each test.
  // Alternatively, you can enable
  // automatic resetting in test.ts.
  MockInstance.scope();

  // Let's configure TestBed via MockBuilder.
  // The code below says to mock everything in
  // ProfileModule except ProfileComponent and
  // ReactiveFormsModule.
  beforeEach(() => {
    // The result of MockBuilder should be returned.
    // https://ng-mocks.sudo.eu/api/MockBuilder
    return MockBuilder(ProfileComponent, ProfileModule)
      .keep(ReactiveFormsModule);
    // // or the old-fashioned way
    // return TestBed.configureTestingModule({
    //   imports: [
    //     MockModule(SharedModule), // mock
    //     ReactiveFormsModule, // real
    //   ],
    //   declarations: [
    //     ProfileComponent, // real
    //     MockPipe(CurrencyPipe), // mock
    //     MockDirective(HoverDirective), // mock
    //   ],
    //   providers: [
    //     MockProvider(AuthService), // mock
    //   ],
    // }).compileComponents();
  });

  // A test to ensure that ProfileComponent
  // can be created.
  it('should be created', () => {
    // MockRender is an advanced version of
    // TestBed.createComponent.
    // It respects all lifecycle hooks,
    // onPush change detection, and creates a
    // wrapper component with a template like
    // <app-root ...allInputs></profile>
    // and renders it.
    // It also respects all lifecycle hooks.
    // https://ng-mocks.sudo.eu/api/MockRender
    const fixture = MockRender(ProfileComponent);

    expect(fixture.point.componentInstance).toEqual(
      jasmine.any(ProfileComponent),
    );
  });

  // A test to ensure that the component listens
  // on ctrl+s hotkey.
  it('saves on ctrl+s hot key', () => {
    // A fake profile.
    const profile = {
      email: '[email protected]',
      firstName: 'testFirst2',
      lastName: 'testLast2',
    };

    // A spy to track save calls.
    // MockInstance helps configure mock
    // providers, declarations and modules
    // before their initialization and usage.
    // https://ng-mocks.sudo.eu/api/MockInstance
    const spySave = MockInstance(
      StorageService,
      'save',
      jasmine.createSpy(),
      // or, for Jest
      // jest.fn(),
    );

    // Renders <profile [profile]="params.profile">
    // </profile>.
    // https://ng-mocks.sudo.eu/api/MockRender
    const { point } = MockRender(
      ProfileComponent,
      { profile }, // bindings
    );

    // Let's change the value of the form control
    // for email addresses with a random value.
    // ngMocks.change finds a related control
    // value accessor and updates it properly.
    // https://ng-mocks.sudo.eu/api/ngMocks/change
    ngMocks.change(
      '[name=email]', // css selector
      '[email protected]', // an email address
    );

    // Let's ensure that nothing has been called.
    expect(spySave).not.toHaveBeenCalled();

    // Let's assume that there is a host listener
    // for a keyboard combination of ctrl+s,
    // and we want to trigger it.
    // ngMocks.trigger helps to emit events via
    // simple interface.
    // https://ng-mocks.sudo.eu/api/ngMocks/trigger
    ngMocks.trigger(point, 'keyup.control.s');

    // The spy should be called with the profile
    // and the random email address.
    expect(spySave).toHaveBeenCalledWith({
      email: '[email protected]',
      firstName: profile.firstName,
      lastName: profile.lastName,
    });
  });
});

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Very short introduction​

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Very short introduction

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