解决方法 => 错误：Nest 无法解析 MemberService 的依赖关系答案

【问题标题】：Methodic way to solve => Error: Nest can't resolve dependencies of the MemberService解决方法 => 错误：Nest 无法解析 MemberService 的依赖关系
【发布时间】：2021-07-28 18:46:58
【问题描述】：

我的任务是向遗留项目添加单元测试。

在给定模块上引入单元测试之前，我正在做“冒烟测试”。基本上使脚手架“应该定义”通过。

因此我面临经典错误：

Error: Nest can't resolve dependencies of the MemberService (NestWinston, ?, RedisService, RepoService, SqsService). Please make sure that the argument Object at index [1] is available in the RootTestModule context.

Potential solutions:
- If Object is a provider, is it part of the current RootTestModule?
- If Object is exported from a separate @Module, is that module imported within RootTestModule?
  @Module({
    imports: [ /* the Module containing Object */ ]
  })

我怎样才能确定该模块需要什么？

这是一个遗留项目，因此很难获得信息，我的同事也无法完全帮助我。

什么是解决这个问题的好方法？

编辑：这是 MemberService 的构造函数


@Injectable()
export class MemberService {
  private readonly sendMail: any;
  private algoliaClient: any;
  private index: AlgoliaSearch.SearchIndex;
  private readonly sendLog: any;

  constructor(
    @Inject(WINSTON_MODULE_NEST_PROVIDER)
    private readonly cacheService: CacheService,
    private readonly logger: LoggerService,
    private readonly redisService: RedisService,
    private readonly repoService: RepoService,
    private readonly sqsService: SqsService,
  ) {
    const { sendMessage: sendLog } = this.sqsService.initQueue('logs');
    this.sendLog = sendLog;
    const { sendMessage: sendMail } = this.sqsService.initQueue('mail');
    this.sendMail = sendMail;
    this.algoliaClient = AlgoliaSearch.default(ALGOLIA_APP_ID, ALGOLIA_API_KEY);
    this.index = this.algoliaClient.initIndex(`${APP_ENV}_NETWORK_MEMBERS`);
  }

编辑 2：这是我的测试模块设置

  beforeEach(async () => {
    const module: TestingModule = await Test.createTestingModule({
      imports: [
        TypeOrmModule.forRoot(DB_CONNECTION),
        RepoModule,
        RedisModule.register({
          url: REDIS_URL,
          autoResubscribe: false,
        }),
      ],
      providers: [
        CacheService,
        MemberService,
        SqsService,
        {
          provide: WINSTON_MODULE_NEST_PROVIDER,
          useFactory: () =>
            Winston.createLogger({
              transports: [new Winston.transports.Console()],
            }),
        },
      ],
    }).compile();

    service = module.get<MemberService>(MemberService);
  });

【问题讨论】：

这是常见的；看看stackoverflow.com/…，如果您向我们展示您的MemberService 的constructor 方法如何，我们可以为您提供帮助，顺便说一句
感谢@MicaelLevi 的回答，我已经进行了相应的编辑。
据我所知，LoggerService 丢失了。根据 MemberService 构造函数参数，预计提供者。
是的。您的测试模块是如何设置的？您必须执行此处显示的操作：docs.nestjs.com/techniques/database#testing-1
已编辑。出于某种原因，我无法在我的测试模块中导入LoggerService。

标签： typescript testing dependency-injection dependencies nestjs

【解决方案1】：

根据您显示的代码，@Inject(WINSTON_MODULE_NEST_PROVIDER) 位于错误的位置。您正在用WINSTON_MODULE_NEST_PROVIDER 覆盖CacheService 的注入令牌，并且没有为LoggerService 提供任何东西（它本身就是一个接口，被转译为{}）。将 @Inject() 行下移 1 以使其修改 private readonly logger: LoggerService ，然后您就可以开始了。

@Injectable()
export class MemberService {
  private readonly sendMail: any;
  private algoliaClient: any;
  private index: AlgoliaSearch.SearchIndex;
  private readonly sendLog: any;

  constructor(
    private readonly cacheService: CacheService,
    @Inject(WINSTON_MODULE_NEST_PROVIDER)
    private readonly logger: LoggerService,
    private readonly redisService: RedisService,
    private readonly repoService: RepoService,
    private readonly sqsService: SqsService,
  ) {
    const { sendMessage: sendLog } = this.sqsService.initQueue('logs');
    this.sendLog = sendLog;
    const { sendMessage: sendMail } = this.sqsService.initQueue('mail');
    this.sendMail = sendMail;
    this.algoliaClient = AlgoliaSearch.default(ALGOLIA_APP_ID, ALGOLIA_API_KEY);
    this.index = this.algoliaClient.initIndex(`${APP_ENV}_NETWORK_MEMBERS`);
  }

【讨论】：