Nest.js 单元测试中的模拟注入服务

Question

我想测试我的服务（位置服务）。在此位置服务中，我注入存储库和其他名为 GeoLocationService 的服务，但当我尝试模拟此 GeoLocationService 时陷入困境。

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它给我一个错误

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GeolocationService \xe2\x80\xba should be defined\n\n    Nest can't resolve dependencies of the GeolocationService (?). Please make sure that the argument HttpService at index [0] is available in the RootTestModule context.\n\n

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这是提供商的代码

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@Injectable()\nexport class LocationService {\n  constructor(\n    @Inject('LOCATION_REPOSITORY')\n    private locationRepository: Repository<Location>,\n\n    private geolocationService: GeolocationService, // this is actually what I ma trying to mock\n  ) {}\n\n  async getAllLocations(): Promise<Object> {\nreturn await this.locationRepository.find()\n  }\n....\n}\n\n

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这是测试代码

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describe('LocationService', () => {\n  let service: LocationService;\n  let repo: Repository<Location>;\n\n  beforeEach(async () => {\n    const module: TestingModule = await Test.createTestingModule({\n      imports: [GeolocationModule],\n      providers: [\n        LocationService,\n        {\n          provide: getRepositoryToken(Location),\n          useClass: Repository,\n        },\n      ],\n    }).compile();\n\n    service = module.get<LocationService>(LocationService);\n    repo = module.get<Repository<Location>>(getRepositoryToken(Location));\n  });\n\n  it('should be defined', () => {\n    expect(service).toBeDefined();\n  });\n});\n

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Answer 1

imports: [GeolocationModule]您应该提供 的模拟，而不是添加GeolocationService。该模拟应该与 具有相同的方法名称GeolocationService，但它们都可以被存根 ( jest.fn()) 或者它们可以有一些返回值 ( jest.fn().mockResolved/ReturnedValue())。一般来说，自定义提供程序（添加到providers数组中）将如下所示：

{
  provide: GeolocationService,
  useValue: {
    method1: jest.fn(),
    method2: jest.fn(),
  }
}

您可以在此存储库中找到大量模拟示例。