Angular:使用MockBackend测试HTTP,是否真的需要async()？

Question

我正在MockBackend测试依赖的代码@angular/http.
Web上的所有示例都使用异步测试设置,如下所示:
thoughtram:在Angular中使用Http测试服务

describe('getVideos()', () => {

  it('should return an Observable<Array<Video>>',
      async(inject([VideoService, MockBackend], (videoService, mockBackend) => {

      videoService.getVideos().subscribe((videos) => {
        expect(videos.length).toBe(4);
        expect(videos[0].name).toEqual('Video 0');
        expect(videos[1].name).toEqual('Video 1');
        expect(videos[2].name).toEqual('Video 2');
        expect(videos[3].name).toEqual('Video 3');

        expect("THIS TEST IS FALSE POSITIVE").toEqual(false); 
      });

      const mockResponse = {
        data: [
          { id: 0, name: 'Video 0' },
          { id: 1, name: 'Video 1' },
          { id: 2, name: 'Video 2' },
          { id: 3, name: 'Video 3' }
        ]
      };

      mockBackend.connections.subscribe((connection) => {
        connection.mockRespond(new Response(new ResponseOptions({
          body: JSON.stringify(mockResponse)
        })));
      });
  })));
});

但是,我试过了,我很确定MockBackend执行完全同步:

describe('getVideos()', () => {

  it('should return an Observable<Array<Video>>',
    inject([VideoService, MockBackend], (videoService, mockBackend) => {

      const mockResponse = {
        data: [
          { id: 0, name: 'Video 0' },
          { id: 1, name: 'Video 1' },
          { id: 2, name: 'Video 2' },
          { id: 3, name: 'Video 3' },
        ]
      };

      mockBackend.connections.subscribe((connection) => {
        connection.mockRespond(new Response(new ResponseOptions({
          body: JSON.stringify(mockResponse)
        })));
      });

      let videos;
      videoService.getVideos().subscribe(v => videos = v);

      // synchronous code!?
      expect(videos.length).toBe(4);
      expect(videos[0].name).toEqual('Video 0');
      expect(videos[1].name).toEqual('Video 1');
      expect(videos[2].name).toEqual('Video 2');
      expect(videos[3].name).toEqual('Video 3');
    }));
});

我在这里创建了一个关于plunker的完整示例:https://plnkr.co/edit/I3N9zL ？ p = preview

自撰写这些文章以来,一定有些变化.有人能指出我那个突破性的变化吗？还是我错过了一个重要的事实？

Answer 1

你的假设完全正确,它MockConnection.mockRespond()会同步发出.async()在这个特定的测试中不需要.

我是您在问题中提到的文章的作者,我已相应地更新了它.

非常感谢您指出这一点!