使用真实 HTTP 进行 Angular Jasmine 与服务的集成测试

[角度版本：2.4.5]

我正在尝试编写一个 Angular 集成组件单元测试，其中包含利用内置 Angular HTTP 库的服务。但我无法实例化我的服务类：要么服务未定义，要么我收到“错误：无法解析“RequestOptions”的所有参数（？）”。

据我所知，通常您会模拟后端（已在其他单元测试中成功完成）或使用 Protractor。其他 SO 问题引用 Angular 1 或有似乎不起作用的答案。起始代码：

    @Injectable()
    export class ProjectService {
        projectFeature: IProjectFeature;

        constructor(private http: Http) { }

        getProjects(): Observable<IProjects> {
        return this.http.get("/api/Projects")
            .map((response: Response) => response.json() || {})
            .catch(this.handleError);
         }
    }

     // Jasmine spec file:   
        beforeEach(async(() => {
        TestBed.configureTestingModule({
            providers: [
                Http,
                ProjectService,  // service that leverages HTTP
                ConnectionBackend
                //RequestOptions  // removed b/c otherwise can't find parameters error happens
            ],
            imports: [
               HttpModule
            ] 
        });
    }));

    it('sample test', async(() => {
        var projectService = TestBed.get(ProjectService);
        var comp = new ProjectComponent(projectService);
        comp.ngOnInit();  // internally, calls projectService.getProjects()
        expect(comp.projects[0].name).toEqual("Sample Project Name");
    })); 

HttpModule模块应提供在TestBed模块配置。在那之后，Http执行真正的 XHR 请求，不需要额外的操作，demo http://plnkr.co/edit/9xEB6myPEtXMmLYMXpHu?p=preview:

  beforeEach(() => {
    TestBed.resetTestEnvironment();

    TestBed.initTestEnvironment(
      BrowserDynamicTestingModule,
      platformBrowserDynamicTesting()
    );

    TestBed.configureTestingModule({
      imports: [
        HttpModule
      ]
    });

  });

  it('should do XHR', async(inject([Http], (http) => {
    http.get('test.json').subscribe(res => {
      expect(res.json()).toBe(1);
    });
  })));