NgRx Marbles 测试效果 returns 奇怪的错误

Question

我有一个使用 NgRx Effects 的 Angular 5 应用程序。其中一个 Effects 通过将用户输入的数据传递到 NodeJS 后端来处理网站注册。 Effect 完全按预期工作，但是当我尝试使用 Marbles 对其进行单元测试时，出现了一个奇怪的错误。

这是效果：

@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 Marbles 的单元测试。它遵循 Todd Motto 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 Karma 中得到的错误：

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 }) }).

我从这个相当神秘的错误消息中推断出触发了 trySignup 操作，但没有触发 unsuccessfulSignup 操作。有谁知道为什么会这样？

谢谢！

Answer 1

亚历克斯，

您的 switchMap 将流切换到您未存根或返回的 http.post 流。您需要先从 HttpClientTestingModule 发出错误，才能触发 catch 事件。

请参阅下面的 link 示例：

https://medium.com/@Jestfer/testing-http-requests-in-angular-with-httpclienttestingmodule-3880ceac74cf

NgRx Marbles 测试效果 returns 奇怪的错误

NgRx Marbles Testing of an Effect returns weird error

angular

angular5

ngrx

ngrx-effects

jasmine-marbles