Presenter.java

public class Presenter {

    private final NetworkApi api;
    
    public Presenter(NetworkApi api) {
        this.api = api;
    }

    public void loadData() {
        view.showProgress(true);
        api.loadData()
           .subscribeOn(Schedulers.io())
           .observeOn(AndroidSchedulers.mainThread())
           .subscribe(userProfile -> {
               view.showProgress(false);
               view.showUserProfile(userProfile);
           });
    }
}

TestPresenter.java

public class TestPresenter {

    private Presenter underTest;

    private View mockView;
    private NetworkApi mockNetworkApi;
    
    private FileDataProvider fileReader = new FileDataProvider();

    @Before
    public void setup() throws Exception {
        mockView = mock(View.class);
        mockNetworkApi = mock(NetworkApi.class);
        
        underTest = new Presenter(mockNetworkApi, mockView);
        
        RxAndroidPlugins.getInstance().registerSchedulersHook(new RxAndroidSchedulersHook() {
            @Override
            public Scheduler getMainThreadScheduler() {
                return Schedulers.immediate();
            }
        });
        RxJavaHooks.setOnIOScheduler(scheduler -> Schedulers.immediate());
    }

    @After
    public void tearDown() {
        RxJavaHooks.reset();
        RxAndroidPlugins.getInstance().reset();
    }

    @Test
    public void testLoadData () throws IOException {
        UserProfile response = fileReader.readUserProfile();
        when(mockNetworkApi.loadData()).thenReturn(Observable.just(response));
        
        underTest.loadData();
        
        verify(mockView).showUserProfile(any(UserProfile.class));
    }
}