Angular Testing 可观察量

Question

我有一个寄存器组件，我正在尝试测试它的寄存器功能

  register() {
    this.hasSubmitted = true;
    this._auth.register(this.user).subscribe(result => {
      this.openSnackBar("Registration Successful, Redirecting......", "OK", 2000);
      setTimeout(() => {
        this._router.navigate(['/']);
      },1000)
      this.hasSubmitted = false;
    }, (error) => {
      this.openSnackBar(error, "OK", null)
      this.hasSubmitted = false;
    });
  }

我创建了一个 stub 类并将其注入(inject)到测试平台中，如下所示

 beforeEach((() => {
    TestBed.configureTestingModule({
      declarations: [RegisterComponent],
      imports: [
        ReactiveFormsModule, BrowserAnimationsModule, FormsModule, MatInputModule, MatCheckboxModule, MatIconModule, MatProgressBarModule, MatDialogModule, MatSnackBarModule
      ],
      providers: [
        { provide: AuthService, useClass: AuthStub },
        { provide: Router, useClass: RouterStub },
      ]
    })
      .compileComponents();

      fixture = TestBed.createComponent(RegisterComponent);
      component = fixture.componentInstance;
  }));

但是，当我尝试测试 register 方法时，我收到一条错误消息，指出 cannot read property subscribe of undefined，这是指我的 register 方法中的 subscribe 调用。我似乎无法从模拟 stub 中返回可观察到的值。我做错了什么？

 it('should call register in the auth class once registration is submitted', () => {
    let auth = TestBed.get(AuthService)
    let spy = spyOn(auth, "register");
    component.register();
    expect(spy).toHaveBeenCalled();
  });

export class AuthStub {

  register(): Observable<any> {
    return Observable.empty()
  }
}

Answer 1

这是因为当您监视 一个函数时，它实际上并没有被调用，因此this._auth.register 没有返回任何内容。你应该让 jasmine 从 AuthStub

调用原始函数 register

换行

let spy = spyOn(auth, "register");

到

let spy = spyOn(auth, "register").and.callThrough();