I have test which pass successfully (expectation would be that it fails).

@Test
    fun someTest() = runBlockingTest {
        Dispatchers.setMain(coroutineContext[ContinuationInterceptor] as CoroutineDispatcher)

        val viewModel = arrange()

        viewModel.viewModelScope.launch {
            throw IllegalStateException("mm")
        }
    }

From my understanding problem is

viewModelScope

extension which creates

SupervisorJob

at https://cs.android.com/androidx/platform/frameworks/support/+/androidx-master-dev:lifecycle/lifecycle-viewmodel-ktx/src/main/java/androidx/lifecycle/ViewModel.kt;l=42;drc=9f40e609cef60d1889e2b13d48ba1dbb8aa345e3 What would be appropriate way to make such test method fail?

I think [TestCoroutineDispatcher][https://github.com/Kotlin/kotlinx.coroutines/blob/master/kotlinx-coroutines-test/README.md#providing-an-explicit-testcoroutinedispatcher] is what you need

I am already using it. This line gets it

coroutineContext[ContinuationInterceptor] as CoroutineDispatcher

Is there a reason why you are retrieving the scope associated with

runBlockingTest

and not using an explicit

TestCoroutineDispatcher

like in the guide ?

In my tests I am using it in similar way. Just added everything to single test method for simplicity. Using Example solution gives same result

I tried this myself and it looks like

runBlockingTest

has a bug still that mentioned https://github.com/Kotlin/kotlinx.coroutines/issues/1204 At least looks very similar. Usually for testing ViewModel classes I'm using injected

CoroutineContext

this allow me to be sure that view model is using Test Dispatcher.

I don't think that it is related. I solved that myselft. Related issue is https://github.com/Kotlin/kotlinx.coroutines/issues/1205