@Test public void lightService_findByEnvironment() { Integer ENVIRONMENT = 108; List<LightModel> lights = new ArrayList<>(); when(lightRepository.findByEnvironment(ENVIRONMENT)).thenReturn(Observable.just(lights)); TestSubscriber<List<LightModel>> tester = new TestSubscriber<>(); lightService.findByEnvironment(ENVIRONMENT).subscribe(tester); verify(lightRepository).findByEnvironment(ENVIRONMENT); tester.assertValue(lights); tester.assertCompleted(); tester.assertNoErrors(); }