Mocking ViewModel in Espresso - kotlin

Question

I'm writing Espresso UI test which mocks viewModel, referring GithubBrowserSample
what is the use of "TaskExecutorWithIdlingResourceRule", declaring Junit Rule will take care of IdlingResource?
Even after referring this "TaskExecutorWithIdlingResourceRule" class in my project whenever I build, compiler doesn't throw any error but when I run the test case it shows the Unresolved Error(s)
TaskExecutorWithIdlingResourceRule.kt
import androidx.arch.core.executor.testing.CountingTaskExecutorRule
import androidx.test.espresso.IdlingRegistry
import androidx.test.espresso.IdlingResource
import org.junit.runner.Description
import java.util.UUID
import java.util.concurrent.CopyOnWriteArrayList
import java.util.concurrent.TimeUnit
class TaskExecutorWithIdlingResourceRule : CountingTaskExecutorRule() {
// give it a unique id to workaround an espresso bug where you cannot register/unregister
// an idling resource w/ the same name.
private val id = UUID.randomUUID().toString()
private val idlingResource: IdlingResource = object : IdlingResource {
override fun getName(): String {
return "architecture components idling resource $id"
}
override fun isIdleNow(): Boolean {
return this#TaskExecutorWithIdlingResourceRule.isIdle
}
override fun registerIdleTransitionCallback(callback: IdlingResource.ResourceCallback) {
callbacks.add(callback)
}
}
private val callbacks = CopyOnWriteArrayList<IdlingResource.ResourceCallback>()
override fun starting(description: Description?) {
IdlingRegistry.getInstance().register(idlingResource)
super.starting(description)
}
override fun finished(description: Description?) {
drainTasks(10, TimeUnit.SECONDS)
callbacks.clear()
IdlingRegistry.getInstance().unregister(idlingResource)
super.finished(description)
}
override fun onIdle() {
super.onIdle()
for (callback in callbacks) {
callback.onTransitionToIdle()
}
}
}
Mocktest
#RunWith(AndroidJUnit4::class)
class MockTest {
#Rule
#JvmField
var activityRule = IntentsTestRule(SingleFragmentActivity::class.java, true, true)
#Rule
#JvmField
val executorRule = TaskExecutorWithIdlingResourceRule()
private lateinit var viewModel: SeriesFragmentViewModel
private val uiModelList = mutableListOf<SeriesBaseUIModel>()
private val seriesMutableLiveData = MutableLiveData<List<SeriesBaseUIModel>>()
private val seriesFragment = SeriesFragment()
#Before
fun init(){
viewModel = mock(SeriesFragmentViewModel::class.java)
`when`(viewModel.seriesLiveData).thenReturn(seriesMutableLiveData)
ViewModelUtil.createFor(viewModel)
activityRule.activity.setFragment(seriesFragment)
EspressoTestUtil.disableProgressBarAnimations(activityRule)
}
#Test
fun testLoading()
{
//Thread.sleep(3000)
uiModelList.add(ProgressUIModel())
seriesMutableLiveData.postValue(uiModelList.toList())
onView(withId(R.id.pod_series_recycler_view))
.check(selectedDescendantsMatch(withId(R.id.pod_adapter_series_header_title), isDisplayed()))
onView(withId(R.id.pod_series_recycler_view))
.check(selectedDescendantsMatch(withId(R.id.pod_adapter_series_header_title), withText(R.string.pod_series_header_title_text)))
onView(withId(R.id.pod_series_recycler_view))
.check(selectedDescendantsMatch(withId(R.id.pod_adapter_series_header_description), isDisplayed()))
onView(withId(R.id.pod_series_recycler_view))
.check(selectedDescendantsMatch(withId(R.id.pod_adapter_series_header_title), withText("Hello")))
Thread.sleep(5000)
}
}