@OptIn(ExperimentalCoroutinesApi::class)
class LoadingViewModelTest {

    private val subject by lazy {
        spyk(LoadingViewModel(UnconfinedTestDispatcher()))
    }

@Before
    fun setUp() {
        MockKAnnotations.init(this, relaxed = true)
    }

    @Test
    fun `xyz - when method called then should assign value on xyz`() = runTest {

        subject.checkXyz()
        verify {
            <http://subject.xyz|subject.xyz> = true
        }
    }
}

junit4

1.8.10

Verification failed: call 1 of 1: LoadingViewModel(#3).setXyz(eq(true))) was not called.

Calls to same mock:
1) LoadingViewModel(#3).checkXyz()
2) LoadingViewModel(#3).getTag(androidx.lifecycle.ViewModelCoroutineScope.JOB_KEY)
3) LoadingViewModel(#3).setTagIfAbsent(androidx.lifecycle.ViewModelCoroutineScope.JOB_KEY, androidx.lifecycle.CloseableCoroutineScope@2d5580f6)

delay

ioDispatcher

viewModelScope

fun checkXyz() {
     viewModelScope.launch(ioDispatcher) {
        delay(1000L)
        xyz = true
     }
 }