Develop Reference

Jetpack Data Store #Inject need initialize

I followed this tutorial link
But I met a problem that "kotlin.UninitializedPropertyAccessException: lateinit property splashViewModel has not been initialized"
Here is my code
#Module
#InstallIn(SingletonComponent::class)
object MainModule {
#Provides
#Singleton
fun provideDataStoreRepository(
#ApplicationContext context: Context
) = DataStoreRepository(context = context)
}
val Context.dataStore: DataStore<Preferences> by preferencesDataStore(name = "on_boarding_pref")
class DataStoreRepository(context: Context) {
private object PreferencesKey {
val onBoardingKey = booleanPreferencesKey(name = "on_boarding_completed")
}
private val dataStore = context.dataStore
suspend fun saveOnBoardingState(completed: Boolean) {
dataStore.edit { preferences ->
preferences[PreferencesKey.onBoardingKey] = completed
}
}
fun readOnBoardingState(): Flow<Boolean> {
return dataStore.data
.catch { exception ->
if (exception is IOException) {
emit(emptyPreferences())
} else {
throw exception
}
}
.map { preferences ->
val onBoardingState = preferences[PreferencesKey.onBoardingKey] ?: false
onBoardingState
}
}
}
class SplashViewModel #Inject constructor(
private val repository: DataStoreRepository
) : ViewModel() {
private val _isLoading: MutableState<Boolean> = mutableStateOf(true)
val isLoading: State<Boolean> = _isLoading
private val _startDestination: MutableState<String> = mutableStateOf(Screen.OnboardingFirstScreen.route)
val startDestination: State<String> = _startDestination
init {
viewModelScope.launch {
repository.readOnBoardingState().collect { completed ->
if (completed) {
_startDestination.value = Screen.MainScreen.route
} else {
_startDestination.value = Screen.OnboardingFirstScreen.route
}
}
_isLoading.value = false
}
}
}
And in my main activity
class MainActivity : ComponentActivity() {
#Inject
lateinit var splashViewModel: SplashViewModel
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
installSplashScreen().setKeepOnScreenCondition {
!splashViewModel.isLoading.value
}
setContent{
BottomNavWithBadgesTheme {
val screen by splashViewModel.startDestination
....
}
}
It turned out MainModule object have never been used. Is that problem? I'm new to jetpack data store, I just followed it, so I don't know where is the problem and how to fix it. Thank you in advance.

Firstly, it's not about data store. It is about dependency injection. You are trying to get the data from viewmodel when it is not initialized.
To solve the problem:
Mark your viewmodel class with #HiltViewModel annotation
Remove lateinit var keyword and #Inject annotation from viewmodel in your MainActivity
Your viewmodel must be initialized in onCreate function like that:
viewModel: SplashViewModel = hiltViewModel()

Coroutine advanceTimeBy function doesn't work

I have a simple viewModel:
class myViewModel: ViewModel() {
val someStringStateFlow = MutableStateFlow<String>("")
fun doSomething() {
viewModelScope.launch(DispatcherProvider.Main) {
delay(200)
someStringStateFlow.emit("Updated")
}
}
}
I have a test class:
class SearchViewModelTest : BehaviorSpec({
Dispatchers.setMain(DispatcherProvider(true).Main)
var viewModel = myViewModel()
Given("the view model is initialized") {
runTest {
When("call doSomeThing") {
viewModel.doSomething()
advanceUntilIdle()
advanceTimeBy(5000)
runCurrent()
Then("The stateflow should be updated") {
viewModel.someStringStateFlow.value shouldBe "Updated"
}
}
}
}
DispatcherProvider provides real or test dispatcher:
object DispatcherProvider {
private var isTest: Boolean? = null
operator fun invoke(isTest: Boolean? = null): DispatcherProvider {
this.isTest = isTest
return this
}
val Main: CoroutineDispatcher
get() = getTestDispatcher(isTest) ?: Dispatchers.Main
private fun getTestDispatcher(isTest: Boolean?): CoroutineDispatcher? =
if (isTest == true) testDispatcher else null
private val testDispatcher: CoroutineDispatcher by lazy {
newSingleThreadContext("Test Dispatcher")
}
}
This test should be successful but it fails. advanceTimeBy doesn't work correctly
What is wrong here?
I'm using coroutine version 1.6.4 with the new experimental test framework

Android unit testing using Mockito : can't get the right behaviour for mocks

I am testing my Repository class using Mockito, specifically getProducts() functionality:
class Repository private constructor(private val retrofitService: ApiService) {
companion object {
#Volatile
private var INSTANCE: Repository? = null
fun getInstance(retrofitService: ApiService): Repository {
synchronized(this) {
var instance = INSTANCE
if (instance == null) {
instance = Repository(retrofitService)
}
INSTANCE = instance
return instance
}
}
}
suspend fun getProducts(): ProductsResponse = withContext(IO) {
retrofitService.getProducts()
}
}
This is my test class:
#ExperimentalCoroutinesApi
#RunWith(MockitoJUnitRunner::class)
class RepositoryTest {
// Class under test
private lateinit var repository: Repository
// Executes each task synchronously using Architecture Components.
#get:Rule
val instantExecutorRule = InstantTaskExecutorRule()
// Set the main coroutines dispatcher for unit testing.
#ExperimentalCoroutinesApi
#get:Rule
var mainCoroutineRule = MainCoroutineRule()
#Mock
private lateinit var retrofitService: ApiService
#Before
fun createRepository() {
MockitoAnnotations.initMocks(this)
repository = Repository.getInstance(retrofitService)
}
#Test
fun test() = runBlocking {
// GIVEN
Mockito.`when`(retrofitService.getProducts()).thenReturn(fakeProductsResponse)
// WHEN
val productResponse: ProductsResponse = repository.getProducts()
println("HERE = ${retrofitService.getProducts()}")
// THEN
println("HERE: $productResponse")
MatcherAssert.assertThat(productResponse, `is`(fakeProductsResponse))
}
}
And my ApiService:
interface ApiService {
#GET("https://www...")
suspend fun getProducts(): ProductsResponse
}
When I call repository.getProducts(), it returns null despite the fact, that I explicitly set retrofitService.getProducts() to return fakeProductsResponse, which is being called inside repository's getProducts() method. It should return fakeProductsResponse, but it returns null.
Am I doing wrong mocking or what the problem can be? Thanks...
EDIT: this is my MainCoroutineRule, if you need it
#ExperimentalCoroutinesApi
class MainCoroutineRule(val dispatcher: TestCoroutineDispatcher = TestCoroutineDispatcher()):
TestWatcher(),
TestCoroutineScope by TestCoroutineScope(dispatcher) {
override fun starting(description: Description?) {
super.starting(description)
Dispatchers.setMain(dispatcher)
}
override fun finished(description: Description?) {
super.finished(description)
cleanupTestCoroutines()
Dispatchers.resetMain()
}
}

It might not be a complete solution to your problem, but what I see is that your MainCoroutineRule overrides the mainDispatcher Dispatchers.setMain(dispatcher).
But in
suspend fun getProducts(): ProductsResponse = withContext(IO)
you are explicitely setting an IO Dispatcher.
I recommend always setting the dispatcher from a property you pass via constructor:
class Repository private constructor(
private val retrofitService: ApiService,
private val dispatcher: CoroutineDispatcher) {
companion object {
fun getInstance(retrofitService: ApiService,
dispatcher: CoroutineDispatcher = Dispatchers.IO): Repository {
// ommit code for simplicity
instance = Repository(retrofitService, dispatcher)
// ...
}
}
}
suspend fun getProducts(): ProductsResponse = withContext(dispatcher) {
retrofitService.getProducts()
}
}
Having it a default parameter you do not need to pass it in your regular code, but you can exchange it within your unit test:
class RepositoryTest {
private lateinit var repository: Repository
#get:Rule
var mainCoroutineRule = MainCoroutineRule()
#Mock
private lateinit var retrofitService: ApiService
#Before
fun createRepository() {
MockitoAnnotations.initMocks(this)
repository = Repository.getInstance(retrofitService, mainCoroutineRule.dispatcher)
}
}
For my own unit tests I am using the blocking function of TestCoroutineDispatcher from the CoroutineRule like:
#Test
fun aTest() = mainCoroutineRule.dispatcher.runBlockingTest {
val acutal = classUnderTest.callToSuspendFunction()
// do assertions
}
I hope this will help you a bit.

Correct structure of implementing MVVM LiveData RxJava Dagger Databinding?

MainActivity
class MainActivity : AppCompatActivity() {
#Inject
lateinit var mainViewModelFactory: mainViewModelFactory
private lateinit var mainActivityBinding: ActivityMainBinding
private lateinit var mainViewModel: MainViewModel
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
mainActivityBinding = DataBindingUtil.setContentView(
this,
R.layout.activity_main
)
mainActivityBinding.rvmainRepos.adapter = mainAdapter
AndroidInjection.inject(this)
mainViewModel =
ViewModelProviders.of(
this#MainActivity,
mainViewModelFactory
)[mainViewModel::class.java]
mainActivityBinding.viewmodel = mainViewModel
mainActivityBinding.lifecycleOwner = this
mainViewModel.mainRepoReponse.observe(this, Observer<Response> {
repoList.clear()
it.success?.let { response ->
if (!response.isEmpty()) {
// mainViewModel.saveDataToDb(response)
// mainViewModel.createWorkerForClearingDb()
}
}
})
}
}
MainViewModelFactory
class MainViewModelFactory #Inject constructor(
val mainRepository: mainRepository
) : ViewModelProvider.NewInstanceFactory() {
override fun <T : ViewModel?> create(modelClass: Class<T>) =
with(modelClass) {
when {
isAssignableFrom(mainViewModel::class.java) -> mainViewModel(
mainRepository = mainRepository
)
else -> throw IllegalArgumentException("Unknown ViewModel class: ${modelClass.name}")
}
} as T
}
MainViewModel
class MainViewModel(
val mainRepository: mainRepository
) : ViewModel() {
private val compositeDisposable = CompositeDisposable()
val mainRepoReponse = MutableLiveData<Response>()
val loadingProgress: MutableLiveData<Boolean> = MutableLiveData()
val _loadingProgress: LiveData<Boolean> = loadingProgress
val loadingFailed: MutableLiveData<Boolean> = MutableLiveData()
val _loadingFailed: LiveData<Boolean> = loadingFailed
var isConnected: Boolean = false
fun fetchmainRepos() {
if (isConnected) {
loadingProgress.value = true
compositeDisposable.add(
mainRepository.getmainRepos().subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe({ response ->
run {
saveDataToDb(response)
)
}
},
{ error ->
processResponse(Response(AppConstants.Status.SUCCESS, null, error))
}
)
)
} else {
fetchFromLocal()
}
}
private fun saveDataToDb(response: List<mainRepo>) {
mainRepository.insertmainUsers(response)
.subscribeOn(Schedulers.io())
.observeOn(Schedulers.io())
.subscribe(object : DisposableCompletableObserver() {
override fun onComplete() {
Log.d("Status", "Save Success")
}
override fun onError(e: Throwable) {
Log.d("Status", "error ${e.localizedMessage}")
}
})
}
}
MainRepository
interface MainRepository {
fun getmainRepos(): Single<List<mainRepo>>
fun getAllLocalRecords(): Single<List<mainRepo>>
fun insertmainUsers(repoList: List<mainRepo>): Completable
}
MainRepositoryImpl
class mainRepositoryImpl #Inject constructor(
val apiService: GitHubApi,
val mainDao: AppDao
) : MainRepository {
override fun getAllLocalRecords(): Single<List<mainRepo>> = mainDao.getAllRepos()
override fun insertmainUsers(repoList: List<mainRepo>) :Completable{
return mainDao.insertAllRepos(repoList)
}
override fun getmainRepos(): Single<List<mainRepo>> {
return apiService.getmainGits()
}
}
I'm quite confused with the implementation of MVVM with LiveData and Rxjava, in my MainViewModel I am calling the interface method and implementing it inside ViewModel, also on the response I'm saving the response to db. However, that is a private method, which won't be testable in unit testing in a proper way (because it's private). What is the best practice to call other methods on the completion of one method or i have to implement all the methods inside the implementation class which uses the interface.

Your ViewModel should not care how you are getting the data if you are trying to follow the clean architecture pattern. The logic for fetching the data from local or remote sources should be in the repository in the worst case where you can also save the response. In that case, since you have a contact for the methods, you can easily test them. Ideally, you could break it down even more - adding Usecases/Interactors.

UnitTest coroutines Kotlin usecase MVP

I am trying to mock a response from my usecases, this usecase works with coroutines.
fun getData() {
view?.showLoading()
getProductsUseCase.execute(this::onSuccessApi, this::onErrorApi)
}
My useCase is injected on presenter.
GetProductsUseCase has this code:
class GetProductsUseCase (private var productsRepository: ProductsRepository) : UseCase<MutableMap<String, Product>>() {
override suspend fun executeUseCase(): MutableMap<String, Product> {
val products =productsRepository.getProductsFromApi()
return products
}
}
My BaseUseCase
abstract class UseCase<T> {
abstract suspend fun executeUseCase(): Any
fun execute(
onSuccess: (T) -> Unit,
genericError: () -> Unit) {
GlobalScope.launch {
val result = async {
try {
executeUseCase()
} catch (e: Exception) {
GenericError()
}
}
GlobalScope.launch(Dispatchers.Main) {
when {
result.await() is GenericError -> genericError()
else -> onSuccess(result.await() as T)
}
}
}
}
}
This useCase call my repository:
override suspend fun getProductsFromApi(): MutableMap<String, Product> {
val productsResponse = safeApiCall(
call = {apiService.getProductsList()},
error = "Error fetching products"
)
productsResponse?.let {
return productsMapper.fromResponseToDomain(it)!!
}
return mutableMapOf()
}
Y try to mock my response but test always fails.
#RunWith(MockitoJUnitRunner::class)
class HomePresenterTest {
lateinit var presenter: HomePresenter
#Mock
lateinit var view: HomeView
#Mock
lateinit var getProductsUseCase: GetProductsUseCase
#Mock
lateinit var updateProductsUseCase: UpdateProductsUseCase
private lateinit var products: MutableMap<String, Product>
private val testDispatcher = TestCoroutineDispatcher()
private val testScope = TestCoroutineScope(testDispatcher)
#Mock
lateinit var productsRepository:ProductsRepositoryImpl
#Before
fun setUp() {
Dispatchers.setMain(testDispatcher)
products = ProductsMotherObject.createEmptyModel()
presenter = HomePresenter(view, getProductsUseCase, updateProductsUseCase, products)
}
#After
fun after() {
Dispatchers.resetMain()
testScope.cleanupTestCoroutines()
}
//...
#Test
fun a() = testScope.runBlockingTest {
setTasksNotAvailable(productsRepository)
presenter.getDataFromApi()
verify(view).setUpRecyclerView(products.values.toMutableList())
}
private suspend fun setTasksNotAvailable(dataSource: ProductsRepository) {
`when`(dataSource.getProductsFromApi()).thenReturn((mutableMapOf()))
}
}
I don't know what is happening. The log says:
"Wanted but not invoked:
view.setUpRecyclerView([]);
-> at com.myProject.HomePresenterTest$a$1.invokeSuspend(HomePresenterTest.kt:165)
However, there was exactly 1 interaction with this mock:
view.showLoading();"

The problem is with how you create your GetProductsUseCase.
You're not creating it with the mocked version of your ProductsRepository, yet you're mocking the ProductsRepository calls.
Try to create the GetProductsUseCase manually and not using a #Mock
// no #Mock
lateinit var getProductsUseCase: GetProductsUseCase
#Before
fun setUp() {
// ...
// after your mocks are initialized...
getProductsUseCase = GetProductsUseCase(productsRepository) //<- this uses mocked ProductsRepository
}