How to use the @angular/fire/.AngularFireModule.initializeApp function in @angular/fire

beforeEach(async(() => {
    TestBed.configureTestingModule({
      imports: [
        RouterTestingModule,
        CoreModule,
        UploadsModule,
        UiModule,
        NotesModule,
        AngularFireModule.initializeApp(environment.firebase, 'firestarter'),
        AngularFirestoreModule,
        AngularFireAuthModule,
        AngularFireStorageModule
      ],
      declarations: [AppComponent]
    }).compileComponents();
  }));
  it('should create the app', async(() => {