unit-testing - Jasmine route spy - undefined 不是对象(评估 'navigate.calls.mostRecent().args' )

Question

我正在尝试对使用路由的 angular2 组件进行单元测试。我有:

class MockRouter {
}

class MockAuth {
  isLoggedIn(){
    return false;
  }
}

describe('Home', () => {
  beforeEach(() => TestBed.configureTestingModule({
    providers: [
      BaseRequestOptions,
      { provide: Router, useClass: MockRouter },
      HomeComponent,
      { provide: AuthenticationService, useClass: MockAuth }
    ]
  }));

  it('should navigate to login', inject([HomeComponent], (home: HomeComponent) => {
    let navigate = jasmine.createSpy('navigate');
    expect(navigate.calls.mostRecent().args[0]).toEqual(['/login']);
  }));
});

但我收到错误:

TypeError: undefined is not an object (evaluating 'navigate.calls.mostRecent().args') in config/spec-bundle.js (line 41757)

我认为 Jasmine spy 是正确的方法，但我错过了一些东西——我做错了什么？

Answer 1

您应该将 spy 添加到 MockRouter 类中。这样 spy 就可以监视 Router

中的 navigate 调用

class MockRouter {
  navigate = jasmine.createSpy('navigate');
}

describe('Home', () => {
  let mockRouter;
  let fixture;
  let component: HomeComponent;

  beforeEach(() => {
     mockRouter = new MockRouter();
     TestBed.configureTestingModule({
        declarations: [ HomeComponent ]
        providers: [
          BaseRequestOptions,
          { provide: Router, useValue: mockRouter },
          { provide: AuthenticationService, useClass: MockAuth }
        ]
      });
      fixture = TestBed.createComponent(HomeComponent);
      component = fixture.createComponent;
  });

  it('should navigate to login', () => {
    // calls component.ngOnInit
    fixture.detectChanges();

    // assuming some navigation has been done
    expect(mockRouter.navigate).toHaveBeenCalledWith(['/login']);
  });
});

注意事项:

• HomeComponent 在 declarations 中，不在 providers
中
• 我们在测试中持有对 mock 的引用，并在配置时使用 useValue 而不是 useClass