如何正确模拟角度服务？Karma Jasmine测试:预计间谍service.getShipPhotos会被调用一次。它被调用了0次

// 导入所需的依赖项
import { TestBed, inject } from '@angular/core/testing';
import { YourService } from './your-service';

describe('YourService', () => {
  let service: YourService;
  let spy: jasmine.Spy;

  beforeEach(() => {
    TestBed.configureTestingModule({
      providers: [YourService]
    });

    service = TestBed.inject(YourService);
    spy = spyOn(service, 'getShipPhotos');
  });

  it('should correctly simulate the service call', () => {
    // 执行测试代码，调用相关函数
    // ...

    // 断言间谍函数被调用一次
    expect(spy).toHaveBeenCalledTimes(1);
  });
});