@Test
  public void prepareJob_messenger() {
    JobInvocation jobInvocation = receiver.prepareJob(callbackMock, new Bundle());
    assertNull(jobInvocation);
    verify(callbackMock).jobFinished(JobService.RESULT_FAIL_NORETRY);
  }
The default ShadowMessenger implementation causes NPEs when using the {@link
Messenger#Messenger(Handler)} constructor. We create our own empty Shadow so we can just use
the standard Android implementation, which is totally fine.

@see <a href="https://github.com/robolectric/robolectric/issues/2246">Robolectric issue</a>
jobdispatcher/src/test/java/com/firebase/jobdispatcher/GooglePlayReceiverTest.java