Selector.kt

class Selector(private dao: Dao,
               dispatcher: CoroutineContext = Dispatchers.IO) : CoroutineScope, ViewModel() {
               
    private val job = Job()
    override val coroutineContext = dispatcher + job

    fun selectById(id: Int) {
        launch {
            delay(5000)
            dao.syncOperationWith(id)
        }
    }

    override fun onCleared() {
        super.onCleared()
        job.cancel()
    }
}

SelectorTest.kt

runBlocking {
    val testedObject = Selector(mockDao, coroutineContext)
    testedObject.selectById(1337)
    verify(mockDao).syncOperationWith(1337)
}

Like this, it goes in error

Exception in thread "main @coroutine#2" java.lang.StackOverflowError
	at kotlinx.coroutines.EventLoopBase$DelayedTask.schedule(EventLoop.kt:322)
	at kotlinx.coroutines.EventLoopBase.scheduleImpl(EventLoop.kt:264)
	at kotlinx.coroutines.EventLoopBase.schedule$kotlinx_coroutines_core(EventLoop.kt:248)
        ...
        at kotlinx.coroutines.EventLoopBase.schedule$kotlinx_coroutines_core(EventLoop.kt:248)