NgRx弹珠效果测试返回奇怪错误

我有一个使用NgRx效果的Angular 5应用程序。其中一种效果通过将用户输入的数据传递到NodeJS后端来处理网站注册。效果完全符合预期,但当我试图用弹珠对其进行单元测试时,我得到了一个奇怪的错误。

这就是效果:

@Effect()
  authSignup$ = this.actions$
    .ofType(AuthActions.TRY_SIGNUP)
    .switchMap((signUpData: {
      first_name: string,
      last_name: string,
      username: string,
      password: string,
      type: string,
      agreement: boolean
    }) =>
      this.httpClient.post(
      '/custom-endpoint',
      {
        first_name: signUpData.first_name,
        last_name: signUpData.last_name,
        username: signUpData.username,
        password: signUpData.password,
        type: signUpData.type,
        agreement: signUpData.agreement
      },
      {
        headers: new HttpHeaders({
          'Content-Type':  'application/json'
        })
      })
      .map((res) => {
        return new AuthActions.SuccessfulSignup();
      })
      .catch((error: {reason: string}) => {
        return Observable.of(new AuthActions.UnsuccessfulSignup({reason: error.reason}))
      })
    );

这是大理石的单元测试。它遵循托德·格言的NgRx效果测试指南。

export class TestActions extends Actions {
  constructor() {
    super(empty());
  }

  set stream(source: Observable<any>) {
    this.source = source;
  }
}

export function getTestActions() {
  return new TestActions();
}

fdescribe('AuthEffects', () => {

  let actions$: TestActions;
  let effects: fromEffects.AuthEffects;

  beforeEach(() => {
    TestBed.configureTestingModule({
      imports: [
        CookieModule.forRoot(),
        StoreModule.forRoot({...fromGlobal.reducers}),
        RouterTestingModule,
        HttpClientTestingModule
      ],
      providers: [
        fromEffects.AuthEffects,
        CookieAesService,
        { provide: Actions, useFactory: getTestActions },
      ],
    });
    actions$ = TestBed.get(Actions);
    effects = TestBed.get(fromEffects.AuthEffects);
  });

  it('should attempt to Sign Up the user', () => {
    const trySignup = new fromActions.TrySignup({
      first_name: 'test',
      last_name: 'test',
      password: 'test',
      username: 'test@test.com',
      type: 'test',
      agreement: false
    });
    const unsuccessfulSignup = new fromActions.UnsuccessfulSignup({ reason: 'test' });

    actions$.stream = hot('a', { a: trySignup });
    const expected = cold('b', { b: unsuccessfulSignup });
    expect(effects.authSignup$).toBeObservable(expected);
  });
});

最后,这是我在因果报应中的错误:

Expected $.length = 0 to equal 1.
Expected $[0] = undefined to equal Object({ frame: 0, notification: Notification({ kind: 'N', value: UnsuccessfulSignup({ payload: Object({ reason: 'test' }), type: 'UNSUCCESSFUL_SIGNUP' }), error: undefined, hasValue: true }) }).

我从这个相当隐晦的错误信息推断 trySignup 行动被启动了,但没有被取消 unsuccessfulSignup 行动有人知道为什么会这样吗?

谢谢