所以我有一个场景，我试图为一个依赖于另一个mongodb仓库实现的mongodb仓库编写一个单元。假设我们在NestJS中有以下mongoose仓库和模块：
1.用户仓库

@Injectable()
export class UsersRepository extends EntityRepository<UserDocument> {
    constructor(@InjectModel(User.name) userModel: Model<UserDocument>) {
      super(userModel)
    }
}

@Module({
  imports: [
    MongooseModule.forFeature(
      [{ name: User.name, schema: UserSchema }],
      'TEST-V2',
    ),
    OrderModule,
  ],
  controllers: [UserController],
  providers: [UserService, UserRepository],
  exports: [UserService, UserRepository],
})
export class UserModule {}

1.订单仓库

@Injectable()
export class OrdersRepository extends EntityRepository<OrderDocument> {
    constructor(@InjectModel(Order.name) orderModel: Model<OrderDocument>) {
      super(orderModel)
    }
}

@Module({
  imports: [
    MongooseModule.forFeature(
      [{ name: Order.name, schema: OrderSchema }],
      'TEST-V2',
    ),
  ],
  providers: [OrderService, OrderRepository],
  exports: [OrderService, OrderRepository],
})
export class OrderModule {}

UserRepository有一个方法，比如'getOrders'，它使用OrdersRepository从数据库中获取现有订单：

@Injectable()
export class UsersRepository extends EntityRepository<UserDocument> {
    constructor(
      @InjectModel(User.name) userModel: Model<UserDocument>,
      protected readonly orderRepository: OrdersRepository  
     ) {
      super(userModel)
    }
    
    async getOrders(id: string) {
      const orders = await this.orderRepository.find({ userId: id });
    }
}

如何创建一个仓库依赖于另一个仓库的单元？这就是我想象的开始：

describe('TaskConfigRepository', () => {
  let userModel: UserModel;
  let userRepository: UserRepository;
  let orderRepository: OrdersRepository;
  let orderModel: OrderModel;
  let connection: Connection;

  beforeEach(async () => {
    const moduleRef = await Test.createTestingModule({
        imports: [
          ConfigModule.forRoot({
            validationSchema: envVarValidationSchema,
            isGlobal: true,
            cache: true,
            envFilePath: `.env`,
            validationOptions: {
              allowUnknown: true,
              abortEarly: false,
            },
            load: [configuration],
          }),
          MongooseModule.forRootAsync({
            connectionName: 'TEST-V2',
            imports: [ConfigModule],
            inject: [ConfigService],
            useFactory: async (configService: ConfigService) => ({
              uri: configService.get('db.mongo.testv2'),
            }),
          }),
        ],
        providers: [
          UsersRepository,
          OrdersRepository,
          {
            provide: getModelToken(Order.name),
            useClass: OrderModel,
          },
          {
            provide: getModelToken(User.name),
            useClass: UserModel,
          },
        ],
      }).compile();
    ... 
    connection = await moduleRef.get(getConnectionToken('TEST-V2')
    jest.clearAllMocks();
  })

  afterEach(async () => {
      await connection.close();
    });
})

当我向依赖项中添加第二个模型/存储库时，会有一种情况，即connection.close()被认为是未定义的。