UseCase { public void destroy() { if (!mSubscription.isUnsubscribed()) { mSubscription.unsubscribe(); } } protected  UseCase(final ThreadExecutor threadExecutor,
      final PostExecutionThread postExecutionThread); void execute(final Subscriber<T> useCaseSubscriber); void destroy();  }
@Test public void testDestroy() { final TestSubscriber<List<Integer>> testSubscriber = new TestSubscriber<>(); mSut.execute(testSubscriber); mSut.destroy(); testSubscriber.assertUnsubscribed(); testSubscriber.assertNoErrors(); }