    @Test
    public void testAdd()  throws Exception {

        RxPresenter presenter = new RxPresenter();
        Subscription mock = Mockito.mock(Subscription.class);
        when(mock.isUnsubscribed()).thenReturn(false);
        presenter.add(mock);
        presenter.onDestroy();
        verify(mock, times(1)).unsubscribe();
        verify(mock, atLeastOnce()).isUnsubscribed();
        verifyNoMoreInteractions(mock);
    }