I want to create a unit test for my NestJS service, which is a database repository.

I have an error: Nest can't resolve dependencies of the RescuerFunctionRepository (?). Please make sure that the argument "RescuerFunctionRepository" at index [0] is available in the RootTestModule context..

The code:

describe('RescuerFunctionRepository', () => {
  let repository: RescuerFunctionRepository

  beforeEach(async () => {
    const module: TestingModule = await Test.createTestingModule({
      providers: [RescuerFunctionRepository],
    }).compile()

    repository = module.get<RescuerFunctionRepository>(RescuerFunctionRepository)
  })

    it('should be defined', () => {
      expect(repository).toBeDefined()
    })
})

It happens also when I add into Test.createTestingModule() an import statement with my module when I have registered SequelizeModule.

The structure of modules:

• AppModule imports CommonModule.
• CommonModule imports and exports DatabaseModule.
• The DatabaseModule imports SequelizeModule and registers it using forRootAsync. All of the repositories are registered as providers and are exported.

How can I resolve this error?