I'm trying to implement a generic spy class to be ...

# announcements

[dave08]

I'm trying to implement a generic spy class to be used in tests for interfaces derived from a base UseCase interface... is there any way to make the spies generic? Or does one have to be made for each derived interface? (See thread for code)

[dave08]

interface ResultUseCase<in Request : Any, out Response> : UseCase<Request, Result<Response, DomainError>> {
    override suspend fun invoke(request: Request): Result<Response, DomainError>
}

[dave08]

interface UseCase<in Request : Any, out Response> {
    suspend operator fun invoke(request: Request): Response?
}

[dave08]

class ResultUseCaseSpy<Request : Any, Response>(
    var block: (suspend (Request) -> Result<Response, DomainError>)? = null
): ResultUseCase<Request, Response> {
    var request: Request? = null
        private set

    override suspend fun invoke(request: Request): Result<Response, DomainError> {
        this.request = request

        return block?.invoke(request) ?: error("No response provided for $request.")
    }
}

[dave08]

I want to derive from ResultUseCase an interface that provides the generic params:
interface SomeUseCase : ResultUseCase<SomeRequest, SomeResult>, and still be able to spy that in my tests with one Spy implementation...