@Test
  public void lightService_delete() {
    String LIGHT_UUID = "myUuid";

    when(lightRepository.delete(LIGHT_UUID)).thenReturn(Observable.just(null));

    TestSubscriber<Void> tester = new TestSubscriber<>();
    lightService.delete(LIGHT_UUID).subscribe(tester);

    verify(lightRepository).delete(LIGHT_UUID);

    tester.assertCompleted();
    tester.assertNoErrors();
  }