如何测试是否从组件角度调用了服务

Question

我有一个组件，它在初始化时从我的服务中调用getAllUsers（）方法，而getAllUsers（）则调用getAllUsersApi。 我想测试两个电话是否都发出了。

这是我的代码中的一些片段：

test.component.ts

ngOnInit(){
  this.getAllUsers();
}
getAllUsers(){
   this.userService.getAllUsersApi('');
}

test.service.ts

getAllUsersApi(){
   return this.http.get('api/endpoint')
}

test.service.spec.ts

it('should call getAllUsers method on init'){
  spyOn(userService, 'getAllUsersApi');
  spyOn(component, 'getAllUsers');
  component.ngOnInit();
  expect(component.getAllUsers).toHaveBeenCalled();
  expect(userService.getAllUsersApi).toHaveBeenCalled(); // it fails here
}

但它在这里失败： expect(userService.getAllUsersApi).toHaveBeenCalled();

谁能帮我我在做什么错。

Answer 1

测试失败的原因是，您的组件间谍componentSpy实际上用空存根替换了componentSpy中的getAllUsers函数，因此您的getAllUsersApi调用将永远不会发生。 and.callThrough将设置一个间谍程序并确保正在调用原始函数。

我会这样测试：

it('should call getAllUsers method on init', () => {
  // set up spies, could also call a fake method in case you don't want the API call to go through
  const userServiceSpy = spyOn(userService, 'getAllUsersApi').and.callThrough();
  const componentSpy = spyOn(component, 'getAllUsers').and.callThrough();

  // make sure they haven't been called yet
  expect(userServiceSpy).not.toHaveBeenCalled();
  expect(componentSpy).not.toHaveBeenCalled();

  // depending on how your component is set up, fixture.detectChanges() might be enough
  component.ngOnInit();

  expect(userServiceSpy).toHaveBeenCalledTimes(1);
  expect(componentSpy).toHaveBeenCalledTimes(1);
});