Makes Angular testing easier

describe('AppComponent', () => {
  const tb = componentTestBed(AppComponent) // 🛠️ Create the test bed which is re-compiled for each test
    .inject('prefs', Preferences); // 🖇️ Link a key to an injection for all tests, see below 👇

  it('should render title', tb(({ component, query }) => { // 🔋 Access enhanced tools for testing components 
    expect(component.title).toEqual('app-v17');
    const span = query.findElement('.content span');
    expect(span.textContent).toContain('app-v17 app is running!');
  }));

  it('should update preferences on click', tb(({ action, injected: { prefs } }) => { // 🤯 Retrieve injections by autocompletion
    expect(prefs.approved).toBeFalse();
    action.click('#my-button');
    expect(prefs.approved).toBeTrue();
  }));
});

describe('AppService', () => {
  const tb = serviceTestBed(AppService, { httpTesting: true }); // 🛠️ Create the test bed and enable http testing

  it('should fetch cat fact', tb(({ service, http, rx }, done) => {
    const mockRes = { fact: 'string', length: 6 };

    rx.remind = service.getCatFact().subscribe({ // 🧯 Use rx.remind to auto unsubscribe after the end of the test
      next: (res) => {
        expect(res).toEqual(mockRes);
        done();
      },
    });

    http.emitSuccessResponse({ url: service.CAT_FACT_URL, body: mockRes }); // 🎭 Fake the http response of the request that matches the url
  }));
});

npm install --save-dev ngx-testing-tools