[FIXED] MockK: no answer found because the mock is modified from outside

Issue

Hello fellow developers,

i have a following problem:

Let's say I have a class called UseCaseX:

class UseCaseX (private val repository: Repository) {

    override suspend fun invoke(params: Unit?) = repository.call()

}

Now, this UseCaseX is used in a class ViewModel, like this:

    ...
    val result = async { useCaseX.invoke(null) }
    ...

Then I use MockK to mock the UseCaseX in a ViewModelTest, like this:

val useCaseX = mockk<UseCaseX>(relaxUnitFun = true)

And I get the following error:

io.mockk.MockKException: no answer found for: UseCaseX(#7).invoke(null, continuation {})
at io.mockk.impl.stub.MockKStub.defaultAnswer(MockKStub.kt:90)
at io.mockk.impl.stub.MockKStub.answer(MockKStub.kt:42)

So obviously the UseCaseX.invoke(params) function gets extended during async{} with an additional parameter and there is no answer for it so far.

Question: how can I provide the answer for the mock in that case?

Solution

use withContext(Dispatchers.Default) instead of async. Should work!

Answered By - Flo We