Mocking a method inside my test class - mockito

Question

Android Studio 2.3
I have the following method I want to test inside my model class:
public class RecipeListModelImp implements RecipeListModelContract {
private Subscription subscription;
private RecipesAPI recipesAPI;
private RecipeSchedulers recipeSchedulers;
#Inject
public RecipeListModelImp(#NonNull RecipesAPI recipesAPI, #NonNull RecipeSchedulers recipeSchedulers) {
this.recipesAPI = Preconditions.checkNotNull(recipesAPI);
this.recipeSchedulers = Preconditions.checkNotNull(recipeSchedulers);
}
#Override
public void getRecipesFromAPI(final RecipeGetAllListener recipeGetAllListener) {
subscription = recipesAPI.getAllRecipes()
.subscribeOn(recipeSchedulers.getBackgroundScheduler())
.observeOn(recipeSchedulers.getUIScheduler())
.subscribe(new Subscriber<List<Recipe>>() {
#Override
public void onCompleted() {
}
#Override
public void onError(Throwable e) {
recipeGetAllListener.onRecipeGetAllFailure(e.getMessage());
}
#Override
public void onNext(List<Recipe> recipe) {
recipeGetAllListener.onRecipeGetAllSuccess(recipe);
}
});
}
#Override
public void shutdown() {
if(subscription != null && !subscription.isUnsubscribed()) {
subscription.unsubscribe();
}
}
}
Inside my test class I am testing like this:
public class RecipeListModelImpTest {
#Mock Subscription subscription;
#Mock RecipesAPI recipesAPI;
#Mock RecipeListModelContract.RecipeGetAllListener recipeGetAllListener;
#Mock List<Recipe> recipes;
#Inject RecipeSchedulers recipeSchedulers;
private RecipeListModelContract recipeListModel;
#Before
public void setup() {
TestBusbyComponent testBusbyComponent = DaggerTestBusbyComponent.builder()
.mockRecipeSchedulersModule(new MockRecipeSchedulersModule())
.build();
testBusbyComponent.inject(RecipeListModelImpTest.this);
MockitoAnnotations.initMocks(RecipeListModelImpTest.this);
recipeListModel = new RecipeListModelImp(recipesAPI, recipeSchedulers);
}
#Test(expected = NullPointerException.class)
public void testShouldThrowExceptionOnNullParameter() {
recipeListModel = new RecipeListModelImp(null, null);
}
#Test
public void testRecipeListModelShouldNotBeNull() {
assertNotNull(recipeListModel);
}
#Test
public void testShouldGetRecipesFromAPI() {
when(recipesAPI.getAllRecipes()).thenReturn(Observable.just(recipes));
recipeListModel.getRecipesFromAPI(recipeGetAllListener);
verify(recipesAPI, times(1)).getAllRecipes();
verify(recipeGetAllListener, times(1)).onRecipeGetAllSuccess(recipes);
verify(recipeGetAllListener, never()).onRecipeGetAllFailure(anyString());
}
#Test
public void testShouldFailToGetRecipesFromAPI() {
when(recipesAPI.getAllRecipes())
.thenReturn(Observable.<List<Recipe>>error(
new Throwable(new RuntimeException("Failed to get recipes"))));
recipeListModel.getRecipesFromAPI(recipeGetAllListener);
verify(recipesAPI, times(1)).getAllRecipes();
verify(recipeGetAllListener, times(1)).onRecipeGetAllFailure(anyString());
verify(recipeGetAllListener, never()).onRecipeGetAllSuccess(recipes);
}
#Test
public void testShouldShutdown() {
when(subscription.isUnsubscribed()).thenReturn(false);
final Field subscriptionField;
try {
subscriptionField = recipeListModel.getClass().getDeclaredField("subscription");
subscriptionField.setAccessible(true);
subscriptionField.set(recipeListModel, subscription);
} catch(NoSuchFieldException e) {
e.printStackTrace();
}
catch(IllegalAccessException e) {
e.printStackTrace();
}
recipeListModel.shutdown();
verify(subscription, times(1)).unsubscribe();
}
}
However, the problem is the Subscription in my model class is always null so will never enter the if blook. Is there any way to test this with using Mockito or spys?
Many thanks for any suggestions,

Answer 1

You should for testing recipeListModel class, where you have shutdown() method , set mock into this class.
If you don't have set method for subscription in recipeListModel , or constructor param.... ),you can set mock object with reflection like :
#Test
public void testShouldShutdown() {
Subscription subscription = mock(Subscription.class);
when(subscription.isUnsubscribed()).thenReturn(false);
Field subscriptionField = recipeListModel.getClass().getDeclaredField("subscription");
subscriptionField.setAccessible(true);
subscriptionField.set(recipeListModel, subscriptionMock);
recipeListModel.shutdown();
verify(subscription, times(1)).unsubscribe();
}
after your update :
if you can't change way of creation , you should mock it like (full way of creation) , i don't know your api , so it's just idea:
Subscription subscription = mock(Subscription.class);
when(subscription.isUnsubscribed()).thenReturn(false);
// preparation mock for create Subscription
//for recipesAPI.getAllRecipes()
Object mockFor_getAllRecipes = mock(....);
when(recipesAPI.getAllRecipes()).thenReturn(mockFor_getAllRecipes );
//for subscribeOn(recipeSchedulers.getBackgroundScheduler())
Object mockFor_subscribeOn = mock();
when(mockFor_getAllRecipes.subscribeOn(any())).thenReturn(mockFor_subscribeOn);
//for .observeOn(recipeSchedulers.getUIScheduler())
Object mockFor_observeOn = mock();
when(mockFor_subscribeOn .observeOn(any())).thenReturn(observeOn);
// for .subscribe
when(observeOn.subscribe(any()).thenReturn(subscription);