How to test Coroutines in ViewModel

Transcript

1. How to test Coroutines in ViewModel 2019.11.11 potatotips #66 Hiroyuki

   Kusu ( @hkusu_ )

2. About me

3. class MainViewModel(private val itemRepository: ItemRepository) : ViewModel() { private val

   _itemListStatus = MutableLiveData<Status<List<Item>>>() val itemListStatus = _itemListStatus.distinctUntilChanged() fun loadItemList() { viewModelScope.launch { _itemListStatus.value = Status.Loading runCatching { withContext(Dispatchers.IO) { itemRepository.getItemList() } } .onSuccess { _itemListStatus.value = Status.Success(it) } .onFailure { _itemListStatus.value = Status.Failure(it) } } } } // ... sealed class Status<out T> { object Loading : Status<Nothing>() data class Success<T>(val data: T) : Status<T>() data class Failure(val throwable: Throwable) : Status<Nothing>() } MainViewModel ͜ͷ ViewModel ͷςετίʔυΛॻ͍ͯΈΔ

4. @ExperimentalCoroutinesApi class TestCoroutinesRule : TestWatcher() { override fun starting(description: Description?)

   { super.starting(description) Dispatchers.setMain(Dispatchers.Unconfined) } override fun finished(description: Description?) { super.finished(description) Dispatchers.resetMain() } } ϝΠϯεϨουΛࠩ͠ସ͑Δ (ରviewModelScope༻)

5. @ExperimentalCoroutinesApi class MainViewModelTest { @get:Rule val instantTaskExecutorRule = InstantTaskExecutorRule() @get:Rule

   var testCoroutinesRule = TestCoroutinesRule() private lateinit var mainViewModel: MainViewModel @MockK private lateinit var itemRepository: ItemRepository @Before fun setUp() { MockKAnnotations.init(this, relaxed = true) mainViewModel = MainViewModel(itemRepository) } @Test fun `MainViewModel#loadItemList()`() { // Given val expectItemList = listOf(Item(1, "item1"), Item(2, "item2")) coEvery { itemRepository.getItemList() } answers { expectItemList } val observer = mockk<Observer<Status<List<Item>>>>(relaxUnitFun = true) mainViewModel.itemListStatus.observeForever(observer) // When mainViewModel.loadItemList() // Then coVerify(exactly = 1) { itemRepository.getItemList() } verifySequence { observer.onChanged(Status.Loading) observer.onChanged(Status.Success(expectItemList)) } } } MainViewModelTest ← ඪ४ͷϧʔϧ(ରLiveData༻) ← ઌ΄Ͳ࡞ͬͨϧʔϧ ← Repository͸ϞοΫ͢Δ ← LiveDataͷObserver΋ϞοΫ
6. None

7. class MainViewModel(private val itemRepository: ItemRepository) : ViewModel() { private val

   _itemListStatus = MutableLiveData<Status<List<Item>>>() val itemListStatus = _itemListStatus.distinctUntilChanged() fun loadItemList() { viewModelScope.launch { _itemListStatus.value = Status.Loading delay(5000) // dleay runCatching { withContext(Dispatchers.IO) { Thread.sleep(2000) // ॏ͍ॲཧ delay(4000) // delay itemRepository.getItemList() } } .onSuccess { _itemListStatus.value = Status.Success(it) } .onFailure { _itemListStatus.value = Status.Failure(it) } } } } ͨͩ͠..
8. None

9. // ... @Test fun `MainViewModel#loadItemList()`() { // Given val expectItemList

   = listOf(Item(1, "item1"), Item(2, "item2")) coEvery { itemRepository.getItemList() } answers { expectItemList } val observer = mockk<Observer<Status<List<Item>>>>(relaxUnitFun = true) mainViewModel.itemListStatus.observeForever(observer) // When mainViewModel.loadItemList() // Then coVerify(exactly = 1) { itemRepository.getItemList() } verifySequence { observer.onChanged(Status.Loading) observer.onChanged(Status.Success(expectItemList)) } } MainViewModelTest ← ϝιουͷॲཧ͕ऴΘΔͷΛ଴ͯͯͳ͍

10. class MainViewModel(private val itemRepository: ItemRepository) : ViewModel() { private val

    _itemListStatus = MutableLiveData<Status<List<Item>>>() val itemListStatus = _itemListStatus.distinctUntilChanged() fun loadItemList() { viewModelScope.launch { _itemListStatus.value = Status.Loading delay(5000) // dleay runCatching { withContext(Dispatchers.IO) { Thread.sleep(2000) // ॏ͍ॲཧ delay(4000) // delay itemRepository.getItemList() } } .onSuccess { _itemListStatus.value = Status.Success(it) } .onFailure { _itemListStatus.value = Status.Failure(it) } } } } ← MVVMͰઃܭ͢Δͱ౰વϝιουͷ ໭Γ஋͸Unit MainViewModel Ͳ͏ରࡦ͢Δ͔ʁ

11. ํ๏ᶃ ViewModelͷϝιουͷ ໭Γ஋ͷܕΛ Job ܕʹ͢Δ

12. class MainViewModel(private val itemRepository: ItemRepository) : ViewModel() { private val

    _itemListStatus = MutableLiveData<Status<List<Item>>>() val itemListStatus = _itemListStatus.distinctUntilChanged() fun loadItemList() = viewModelScope.launch { _itemListStatus.value = Status.Loading Thread.sleep(2000) // ॏ͍ॲཧ delay(5000) // dleay runCatching { withContext(Dispatchers.IO) { Thread.sleep(2000) // ॏ͍ॲཧ delay(4000) // delay itemRepository.getItemList() } } .onSuccess { _itemListStatus.value = Status.Success(it) } .onFailure { _itemListStatus.value = Status.Failure(it) } } } MainViewModel ← JobܕΛฦ͢

13. // ... @Test fun `MainViewModel#loadItemList()`() { // Given val expectItemList

    = listOf(Item(1, "item1"), Item(2, "item2")) coEvery { itemRepository.getItemList() } answers { expectItemList } val observer = mockk<Observer<Status<List<Item>>>>(relaxUnitFun = true) mainViewModel.itemListStatus.observeForever(observer) // When runBlocking { mainViewModel.loadItemList().join() } // Then coVerify(exactly = 1) { itemRepository.getItemList() } verifySequence { observer.onChanged(Status.Loading) observer.onChanged(Status.Success(expectItemList)) } } MainViewModelTest JobܕΛjoin()ͯ͠தஅؔ਺Խ

14. • ςετͷҝʹ໭Γ஋ͷܕΛมߋ͢Δ͜ͱʹ఍߅͕ ͋Δ • 1ͭͷϝιουͰίϧʔνϯΛෳ਺ىಈ͍ͨ͠৔ ߹͸ඍົʁ

15. ํ๏ᶄ ςετ࣌ʹ CoroutineScope Λࠩ͠ସ͑Δ

16. class MainViewModel( private val itemRepository: ItemRepository, coroutineScope: CoroutineScope = MainScope()

    ) : ViewModel(), CoroutineScope by coroutineScope { private val _itemListStatus = MutableLiveData<Status<List<Item>>>() val itemListStatus = _itemListStatus.distinctUntilChanged() fun loadItemList() { launch { _itemListStatus.value = Status.Loading Thread.sleep(2000) // ॏ͍ॲཧ delay(5000) // dleay runCatching { withContext(Dispatchers.IO) { Thread.sleep(2000) // ॏ͍ॲཧ delay(4000) // delay itemRepository.getItemList() } } // ... override fun onCleared() { cancel() } // ... MainViewModel viewModelScopeΛར༻͍ͯ͠ͳ͍ͷͰࣗલͰί ϧʔνϯΛΩϟϯηϧ͢Δίʔυ ίϯετϥΫλͰCoroutineScopeΛࠩ ͠ม͑ΕΔΑ͏ʹ͓ͯ͘͠ .. লུͨ͠৔߹͸ MainScope()

17. // ... // @get:Rule // var testCoroutinesRule = TestCoroutinesRule() private

    lateinit var mainViewModel: MainViewModel @MockK private lateinit var itemRepository: ItemRepository @Before fun setUp() { MockKAnnotations.init(this, relaxed = true) // mainViewModel = MainViewModel(itemRepository) } @Test fun `MainViewModel#loadItemList()`() { // Given val expectItemList = listOf(Item(1, "item1"), Item(2, "item2")) coEvery { itemRepository.getItemList() } answers { expectItemList } val observer = mockk<Observer<Status<List<Item>>>>(relaxUnitFun = true) runBlocking { mainViewModel = MainViewModel(itemRepository, this) mainViewModel.itemListStatus.observeForever(observer) // When mainViewModel.loadItemList() } // Then coVerify(exactly = 1) { itemRepository.getItemList() } verifySequence { observer.onChanged(Status.Loading) observer.onChanged(Status.Success(expectItemList)) } } MainViewModelTest ← runBlockingͷείʔϓΛViewModel ΁౉͢

18. • viewModelScope ͸࢖͏͜ͱ͕Ͱ͖ͳ͍ • ςετίʔυͰ runBlocking ͷϒϩοΫ಺Ͱ ViewModel ͷΠϯελϯεΛ࡞੒͢Δඞཁ͕͋ Γςετίʔυ͕ॻ͖ͮΒ͍

19. ํ๏ᶅ TestCoroutineDispatcher Λ࢖͏

20. open class DispatcherProvider { open val main: CoroutineDispatcher = Dispatchers.Main

    open val io: CoroutineDispatcher = Dispatchers.IO } // ... class MainViewModel( private val itemRepository: ItemRepository, private val dispatcherProvider: DispatcherProvider = DispatcherProvider() ) : ViewModel() { private val _itemListStatus = MutableLiveData<Status<List<Item>>>() val itemListStatus = _itemListStatus.distinctUntilChanged() fun loadItemList() { viewModelScope.launch { _itemListStatus.value = Status.Loading Thread.sleep(2000) // ॏ͍ॲཧ delay(5000) // dleay runCatching { withContext(dispatcherProvider.io) { Thread.sleep(2000) // ॏ͍ॲཧ delay(4000) // delay itemRepository.getItemList() } } // ... MainViewModel Dispatchers.XX ͸ࠩ͠ସ͑ΕΔΑ͏ʹ

21. @ExperimentalCoroutinesApi class TestCoroutinesRule : TestWatcher() { val testCoroutineDispatcher = TestCoroutineDispatcher()

    override fun starting(description: Description?) { super.starting(description) Dispatchers.setMain(testCoroutineDispatcher) } override fun finished(description: Description?) { super.finished(description) Dispatchers.resetMain() testCoroutineDispatcher.cleanupTestCoroutines() } } @ExperimentalCoroutinesApi class TestDispatcherProvider(testCoroutineDispatcher: TestCoroutineDispatcher) : DispatcherProvider() { override val main: CoroutineDispatcher = testCoroutineDispatcher override val io: CoroutineDispatcher = testCoroutineDispatcher } TestUtils.kt

22. // ... @Before fun setUp() { MockKAnnotations.init(this, relaxed = true)

    mainViewModel = MainViewModel(itemRepository, TestDispatcherProvider(testCoroutinesRule.testCoroutineDispatcher)) } @Test fun `MainViewModel#loadItemList()`() = testCoroutinesRule.testCoroutineDispatcher.runBlockingTest { // Given val expectItemList = listOf(Item(1, "item1"), Item(2, "item2")) coEvery { itemRepository.getItemList() } answers { expectItemList } val observer = mockk<Observer<Status<List<Item>>>>(relaxUnitFun = true) mainViewModel.itemListStatus.observeForever(observer) // When mainViewModel.loadItemList() advanceUntilIdle() // ςετର৅͕delayΛར༻͍ͯ͠Δ৔߹ͷΈهड़ // Then coVerify(exactly = 1) { itemRepository.getItemList() } verifySequence { observer.onChanged(Status.Loading) observer.onChanged(Status.Success(expectItemList)) } } MainViewModelTest ςετ༻ͷεϨουͷΈͰίϧʔνϯ Λಈ͔ͭͭ͠delayΛίϯτϩʔϧ

23. ͪΐͬͱศརʹ͢Δ

24. @ExperimentalCoroutinesApi class TestCoroutinesRule : TestWatcher() { private val testCoroutineDispatcher =

    TestCoroutineDispatcher() override fun starting(description: Description?) { super.starting(description) Dispatchers.setMain(testCoroutineDispatcher) } override fun finished(description: Description?) { super.finished(description) Dispatchers.resetMain() testCoroutineDispatcher.cleanupTestCoroutines() } fun runBlockingTest(block: suspend TestCoroutineScope.() -> Unit) { testCoroutineDispatcher.runBlockingTest { block.invoke(this) } } val dispatcherProvider: DispatcherProvider get() = TestDispatcherProvider(testCoroutineDispatcher) } @ExperimentalCoroutinesApi class TestDispatcherProvider(testCoroutineDispatcher: TestCoroutineDispatcher) : DispatcherProvider() { override val main: CoroutineDispatcher = testCoroutineDispatcher override val io: CoroutineDispatcher = testCoroutineDispatcher } fun <T> LiveData<T>.createTestObserver(): Observer<T> { val observer: Observer<T> = mockk(relaxUnitFun = true) this.observeForever(observer) return observer } TestUtils.kt

25. // ... @Before fun setUp() { MockKAnnotations.init(this, relaxed = true)

    mainViewModel = MainViewModel(itemRepository, testCoroutinesRule.dispatcherProvider) } @Test fun `MainViewModel#loadItemList()`() = testCoroutinesRule.runBlockingTest { // Given val expectItemList = listOf(Item(1, "item1"), Item(2, "item2")) coEvery { itemRepository.getItemList() } answers { expectItemList } val observer = mainViewModel.itemListStatus.createTestObserver() // When mainViewModel.loadItemList() advanceUntilIdle() // Then coVerify(exactly = 1) { itemRepository.getItemList() } verifySequence { observer.onChanged(Status.Loading) observer.onChanged(Status.Success(expectItemList)) } } MainViewModelTest

26. ·ͱΊ • ViewModel ্ͷ Coroutines ͷॲཧͷ׬ྃΛ଴ͬ ͯςετͷ݁ՌΛݕূ͢Δํ๏Λ̏௨Γઆ໌ͨ͠ • جຊతʹ͸ ํ๏ᶅ

    Ͱςετ͢Ε͹Αͦ͞͏

27. Thank you ! @hkusu_

28. ࢀߟ: build.gradle implementation 'androidx.lifecycle:lifecycle-extensions:2.2.0-rc01' implementation 'androidx.lifecycle:lifecycle-viewmodel-ktx:2.2.0-rc01' implementation 'androidx.lifecycle:lifecycle-livedata-ktx:2.2.0-rc01' // ...

    testImplementation 'junit:junit:4.12' testImplementation 'org.jetbrains.kotlinx:kotlinx-coroutines-test:1.2.2' testImplementation 'androidx.arch.core:core-testing:2.1.0' testImplementation 'io.mockk:mockk:1.9.3' testImplementation 'com.google.truth:truth:1.0'