TestBug.kt

class QuestionViewModel {
	private val state = MutableLiveData<QuestionState>()

	private val currentQuestion: LiveData<Question> = Transformations.map(state) {
		(it as? QuestionState.Loaded)?.data
	}

	val questionTitle: String
		get() = currentQuestion.value?.title.orEmpty
}

class QuestionViewModelTest {

	@JvmField
  @Rule
  val instantExecutor = InstantTaskExecutorRule()
	
	@Test
	fun assertTitle() {
		// Mock data load
		assertEquals("TestTitle", viewModel.questionTitle)
		// The above is false, saying viewModel.questionTitle is empty, because `currentQuestion` value is null.
		// This is as if the Transformations.map() never ran
	}
}