manuelvicnt

class MyViewModel(dependency: ExternalDependency) : ViewModel() {
 
    fun run() {
      viewModelScope.launch {
        dependency.doStuff()
      }
    }
}

class MyViewModelTest {

manuelvicnt

class MainViewModelUnitTest {
  
    @get:Rule
    var coroutinesTestRule = CoroutinesTestRule()
  
    @Test
    fun test() {
        ...
    }
}

manuelvicnt

@ExperimentalCoroutinesApi
class CoroutinesTestRule(
        val testDispatcher: TestCoroutineDispatcher = TestCoroutineDispatcher()
) : TestWatcher() {

    override fun starting(description: Description?) {
        super.starting(description)
        Dispatchers.setMain(testDispatcher)
    }

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internal class CloseableCoroutineScope(
    context: CoroutineContext
) : Closeable, CoroutineScope {
  
    override val coroutineContext: CoroutineContext = context
  
    override fun close() {
        coroutineContext.cancel()
    }
}

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@MainThread
final void clear() {
    mCleared = true;
    // Since clear() is final, this method is still called on mock 
    // objects and in those cases, mBagOfTags is null. It'll always 
    // be empty though because setTagIfAbsent and getTag are not 
    // final so we can skip clearing it
    if (mBagOfTags != null) {
        for (Object value : mBagOfTags.values()) {
            // see comment for the similar call in setTagIfAbsent

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private const val JOB_KEY = "androidx.lifecycle.ViewModelCoroutineScope.JOB_KEY"

val ViewModel.viewModelScope: CoroutineScope
    get() {
        val scope: CoroutineScope? = this.getTag(JOB_KEY)
        if (scope != null) {
            return scope
        }
        return setTagIfAbsent(JOB_KEY,
            CloseableCoroutineScope(SupervisorJob() + Dispatchers.Main.immediate))

manuelvicnt

class MyViewModel : ViewModel() {
  
    /**
     * Heavy operation that cannot be done in the Main Thread
     */
    fun launchDataLoad() {
        viewModelScope.launch {
            sortList()
            // Modify UI
        }

manuelvicnt

class MyViewModel : ViewModel() {

    /**
     * This is the job for all coroutines started by this ViewModel.
     * Cancelling this job will cancel all coroutines started by this ViewModel.
     */
    private val viewModelJob = SupervisorJob()
    
    /**
     * This is the main scope for all coroutines launched by MainViewModel.