Is there a way to `cancelAllChildren` of a `runTest` scope I kotlinlang #coroutines

Lukasz Kalnik

04/13/2022, 2:24 PM

Is there a way to

cancelAllChildren

runTest

scope? I have a test where I inject the test

coroutineContext

into a ViewModel and I want to cancel all running jobs inside the ViewModel when the test ends.

class MyViewModel(coroutineContext: CoroutineContext = Dispatchers.Default) : ViewModel() {
    
    private val coroutineScope = viewModelScope + coroutineContext

    init {
        coroutineScope.launch { myFlow.collect { /* do something with collected items */ } }
    }
}

class MyViewModelTest {

    @Test
    fun testInitMyViewModel() = runTest {
        MyViewModel(coroutineContext) // coroutineContext from test injected here
        // test hangs and times out eventually because myFlow collection is not canceled
    }
}

Trevor Stone

04/13/2022, 2:28 PM

val job = Job()
val coroutineContext: CoroutineContext = coroutineContext + job

job.cancel()

Lukasz Kalnik

04/13/2022, 2:30 PM

Yup, works perfectly! Thanks for a quick and helpful answer.

If only it could be somehow automatized...

coroutineContext

already have a

Job

which I could reuse?

Paul Woitaschek

04/13/2022, 2:53 PM

You can call into the children

Lukasz Kalnik

04/13/2022, 2:58 PM

Paul Woitaschek

04/13/2022, 3:00 PM

Sth like coroutineContext[Job].children().forEach it cancel

Coding on my phone ;-)

Lukasz Kalnik

04/13/2022, 3:04 PM

Thanks, that works!

The part I was missing was the

coroutineContext[Job]

Thank you so much for your help ❤️

Paul Woitaschek

04/13/2022, 3:05 PM

Lukasz Kalnik

04/13/2022, 3:38 PM

You can even do

coroutineContext[Job]?.cancelChildren()