Kotlin mockk how to verify that method was called (in background scope)?

Question

I'm trying to write test for my ViewModel method. Here is part of code from my ViewModel:

  fun makeBackgroundCallAndClose() {
        backgroundScope.launch(genericErrorHandler) {
            interactor.doBackground(null)
        }
        navigate(NavigatorCommand.CloseScreen)
    } 

The essence of the method is to make API call and close the screen without waiting for a response. On a real device, this works as I would expect, however my tests fail.

Here is my test:

  @Test
    fun `test my makeBackgroundCallAndClose`() = runTest(testDispatcher) {
        coEvery { interactor.doBackground(any()) } just runs

        val viewModel = MyViewModel(
            interactor,
            TestScope()
        )

        viewModel.makeBackgroundCallAndClose()
        runCurrent()

        coVerify {
            interactor.doBackground(null)
        }
        
    }

Me test fails with error: Verification failed: call 1 of 1: MyInteractor(interactor#2).doBackground(null(), any())) was not called.

As far as I understand, my test completes until the request doBackground call is completed, I tried to set a timeout, but it did not help, please help me, what am I doing wrong.

Answer 1

It seems the backgroundScope wasn't mocked.

Can you show the MyViewModel constructor? If the second argument is backgroundScope, you should pass your TestScope to viewModel.

@Test
fun `test my makeBackgroundCallAndClose`() = runTest {
    coEvery { interactor.doBackground(any()) } just runs
    // or use coJustRun { interactor.doBackground(any()) }

    val viewModel = MyViewModel(
        interactor,
        this,
    )

    viewModel.makeBackgroundCallAndClose()
    runCurrent()

    coVerify {
        interactor.doBackground(null)
    }
}