Robolectric buildActivity() with Mockito spy?

Question

It seems to me that building an Activity unit test with Robolectric\'s lifecycle utilities (starting with Robolectric.buildActivity()) and spying on the same Ac

Answer 1

At least for the case where the activity is not the object under test, but only a dummy activity which hosts a fragment under test, it is possible to inject a mock into the test activity which can verify interactions with the activity via the communication interface between fragment and activity (following http://developer.android.com/training/basics/fragments/communicating.html).

Answer 2

The answer is using the reflection to replace the "real" Activity object in ActivityController.

@Test
public void someTestMethod() throws NoSuchFieldException, IllegalAccessException {
    ActivityController<LoginActivity> ac = Robolectric.buildActivity(LoginActivity.class);
    LoginActivity spiedActivity = spy(ac.get());

    replaceComponentInActivityController(ac, spiedActivity);

    ac.create();

    // do your work
 }

public static void replaceComponentInActivityController(ActivityController<?> activityController, Activity activity)
        throws NoSuchFieldException, IllegalAccessException {
    Field componentField = ComponentController.class.getDeclaredField("component");
    componentField.setAccessible(true);
    componentField.set(activityController, activity);
}

I test it by Robolectric 3.1, and it's ok.