Cannot verify method invocation method from RxJava Subscriber

Question

I am trying to run a unit test presenter in my android application. The method I'm trying to test is as follows:

@Override
public boolean loadNextPage() {
    if (!mIsLoading) {
        mIsLoading = true;
        if (mViewReference.get() != null) {
            mViewReference.get().showProgress();
        }
        mService.search(mSearchQuery, ++mCurrentPage)
                .subscribeOn(Schedulers.io())
                .observeOn(AndroidSchedulers.mainThread())
                .subscribe(itemsPage -> {
                            mIsLoading = false;
                            mTotalPages = itemsPage.getPagination().getTotalPages();
                            if (mViewReference.get() != null) {
                                mViewReference.get().showMovies(itemsPage.getItems());
                            }
                        },
                        error -> {
                            mIsLoading = false;
                            Log.d(LOG_TAG, error.toString());
                        });
    }
    return mTotalPages == 0 || mCurrentPage < mTotalPages;
}

mServiceis the Retrofit interface, and the method mService.search()returns RxJava Observable<SearchResults>. My unit test code is as follows:

package mobi.zona.presenters;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.Mock;
import org.mockito.runners.MockitoJUnitRunner;

import java.util.ArrayList;
import java.util.List;

import com.example.api.Service;
import com.example.model.Movie;
import com.example.model.SearchResults;
import com.example.views.MoviesListView;
import rx.Observable;

import static org.mockito.Mockito.times;
import static org.mockito.Mockito.verify;
import static org.mockito.Mockito.when;

@RunWith(MockitoJUnitRunner.class)
public class SearchPresenterTest {

    @Mock
    Service mService;
    @Mock
    MoviesListView mMoviesListView;

    @Test
    public void testLoadNextPage() throws Exception {
        String searchQuery = "the hunger games";
        SearchResults searchResults = new SearchResults();
        List<Movie> movies = new ArrayList<>();
        searchResults.setItems(movies);

        when(mService.search(searchQuery, 1)).thenReturn(Observable.just(new SearchResults()));

        MoviesListPresenter presenter = new SearchPresenter(mZonaService, mMoviesListView, searchQuery);
        presenter.loadNextPage();

        verify(mService, times(1)).search(searchQuery, 1);
        verify(mMoviesListView, times(1)).showProgress();
        verify(mMoviesListView, times(1)).showMovies(movies);
    }
}

The problem is the third line verify(mMoviesListView, times(1)).showMovies(movies);- it always fails. Whem I'm trying to debug this test, I see that the control flow never goes into .subscribe(itemPage - {.... I think this is due to the fact that I subscribe to the stream Schedulers.io(), but I have no idea how to fix it. Any ideas? EDIT 1: The presenter has changed to take Scheduleras constructor parameters. The modified test is as follows:

@Test
public void testLoadNextPage() throws Exception {
    String searchQuery = "the hunger games";
    SearchResults searchResults = new SearchResults();
    List<Movie> movies = new ArrayList<>();
    searchResults.setItems(movies);

    when(mZonaService.search(searchQuery, 1)).thenReturn(Observable.just(new SearchResults()));

    MoviesListPresenter presenter = new SearchPresenter(mZonaService, mMoviesListView, searchQuery,
            Schedulers.test(), Schedulers.test());
    presenter.loadNextPage();

    verify(mZonaService, times(1)).search(searchQuery, 1);
    verify(mMoviesListView, times(1)).showProgress();
    verify(mMoviesListView, times(1)).showMovies(movies);
}

:

Wanted but not invoked:
mMoviesListView.showMovies([]);
-> at com.example.presenters.SearchPresenterTest.testLoadNextPage(SearchPresenterTest.java:46)

However, there were other interactions with this mock:
mMoviesListView.showProgress();
-> at com.example.presenters.SearchPresenter.loadNextPage(SearchPresenter.java:41)

Answer 1

/use -cases/model (mService ) Scheduler ( , ).

, subscribeOn mService. .

, mService, "" Scheduler. - Sheduler .

public class MyService {

    private final Scheduler taskScheduler;

    public MyService(Scheduler taskScheduler) {
        this.taskScheduler = taskScheduler;
    }

    // ...

    public Observable<Something> query() {
        return someObservable.subscribeOn(taskScheduler);
    }
}

Schedulers.immediate() Schedulers.io() ( , ).