如何在 ng2 中测试订阅 karma

How to test subscribe with karma in ng2

从服务中我得到了一些流,所以在我的组件中我得到了这样的信息:

this.service.getSome().subscribe(x => this.invokeHere(x));

在我的规格文件中,我有这样的东西

beforeEach(() => {
    fixture = TestBed.createComponent(SomeComponent);
    component = fixture.componentInstance;

    service = fixture.debugElement.injector.get(Service);
    spy = spyOn(service, 'getSome')
        .and.returnValue(Observable.of(serviceStub));

    fixture.detectChanges();
});
it('test observable', inject([MockBackend], (mockBackend: MockBackend) => {
    mockBackend.connections.subscribe((connection: MockConnection) => {
      connection.mockError(new Error());
    });
    service.someRequest()
      .subscribe(() => { },(err) => {
        // your test
      });
  }));