Verify that activity runOnUiThread is called using Robolectric and Mockito

VerifyRunOnUiThread

/*
 * Verifies that an activities runOnUiThread method is called and that
 * appropriate class is called.  In most cases we don't care about
 * actually executing the runOnUiThread, just that it got called.
 * By mocking out the Activity, we can use Mockito's verify method to
 * make sure the method was called, with the expected Runnable class implementation
 * passed into it.
 *
 * By doing this we avoid having to pause Robolectrics's UIScheduler and BackgroundSchedulers
 * and then kick off the task.  Since in this case it isn't actually necessary to run the code as it
 * has it's own unit tests around it, and we don't want to starting getting into integration testing.
 */

@RunWith(RobolectricTestRunner.class)
@Config(emulateSdk = 18)
public class SerenityBackgroundLoadListenerTest {

	View backgroundView;
	Activity activity;

	@Before
	public void setUp() {
		backgroundView = Mockito.mock(View.class);
		activity = Mockito.mock(Activity.class);
		doNothing().when(activity).runOnUiThread(
				any(BackgroundBitmapDisplayer.class));
		when(backgroundView.getContext()).thenReturn(activity);
	}

	@After	
	public void tearDown() {

	}

	@Test
	public void assertThatBackgroundBitmapDisplayerIsRunOnUIThread() {
		SerenityBackgroundLoaderListener listener = new SerenityBackgroundLoaderListener(
				backgroundView, R.drawable.movies);
		listener.onLoadingComplete(null, backgroundView, null);
		verify(activity).runOnUiThread(any(BackgroundBitmapDisplayer.class));
	}
}