如何測試是否從組件角度調用了服務

Question

我有一個組件，它在初始化時從我的服務中調用getAllUsers（）方法，而getAllUsers（）則調用getAllUsersApi。 我想測試兩個電話是否都發出了。

這是我的代碼中的一些片段：

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
}

但它在這里失敗： expect(userService.getAllUsersApi).toHaveBeenCalled();

誰能幫我我在做什么錯。

Answer 1

測試失敗的原因是，您的組件間諜componentSpy實際上用空存根替換了componentSpy中的getAllUsers函數，因此您的getAllUsersApi調用將永遠不會發生。 and.callThrough將設置一個間諜程序並確保正在調用原始函數。

我會這樣測試：

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);
});