Plaid - ShowViewModelTest solution

ShowViewModelTest.kt

class ShotViewModelTest {
    // This CoroutineDispatcher is injected in the ViewModel and use case
    private val testCoroutineDispatcher = TestCoroutineDispatcher()

    @After
    fun tearDown() {
        testCoroutineDispatcher.cleanupTestCoroutines()
    }

    @Test
    fun loadShot_emitsTwoUiModels() = testCoroutineDispatcher.runBlockingTest {
        // 1) Given coroutines have not started yet and the View Model is created
        testCoroutineDispatcher.pauseDispatcher()
        val viewModel = ... // Creates viewModel injecting testCoroutineDispatcher

        // Then the fast result has been emitted
        val fastResult = viewModel.shotUiModel.getOrAwaitValue()
        assertTrue(fastResult.formattedDescription.isEmpty())

        // 2) When the coroutine starts
        testCoroutineDispatcher.resumeDispatcher()

        // 3) Then the slow result has been emitted
        val slowResult = viewModel.shotUiModel.getOrAwaitValue()
        assertTrue(slowResult.formattedDescription.isNotEmpty())
    }
}