Get result from an activity after finish(); in an Android unit test

Question

I'm currently writing some Android unit tests, and while I've gotten most things to work the way I want, one thing has left me kind of stumped.

I have the following code in my activity under test:

Intent result = new Intent();
result.putExtra("test", testinput.getText().toString());
setResult(Activity.RESULT_OK, result);
finish();

I'm trying to figure out how to use Instrumentation (or whatever) to be able to read the result of the activity, or get at the intent after the activity is finished. Can anyone help?

Answer 1

You can use reflection and grab the values directly from the Activity.

protected Intent assertFinishCalledWithResult(int resultCode) {
  assertThat(isFinishCalled(), is(true));
  try {
    Field f = Activity.class.getDeclaredField("mResultCode");
    f.setAccessible(true);
    int actualResultCode = (Integer)f.get(getActivity());
    assertThat(actualResultCode, is(resultCode));
    f = Activity.class.getDeclaredField("mResultData");
    f.setAccessible(true);
    return (Intent)f.get(getActivity());
  } catch (NoSuchFieldException e) {
    throw new RuntimeException("Looks like the Android Activity class has changed it's   private fields for mResultCode or mResultData.  Time to update the reflection code.", e);
  } catch (Exception e) {
    throw new RuntimeException(e);
  }
}

Answer 2

Or you could also use Robolectric and shadow the Activity under test. Then, ShadowActivity provides you with methods to easily know if an Activity is finishing and for retrieving its result code.

As an example, one of my tests looks like this:

@Test
public void testPressingFinishButtonFinishesActivity() {
    mActivity.onCreate(null);
    ShadowActivity shadowActivity = Robolectric.shadowOf(mActivity);

    Button finishButton = (Button) mActivity.findViewById(R.id.finish_button);
    finishButton.performClick();

    assertEquals(DummyActivity.RESULT_CUSTOM, shadowActivity.getResultCode());
    assertTrue(shadowActivity.isFinishing());
}