@Test
public void dispose() {

    MaybeCallbackObserver<Object> mo = new MaybeCallbackObserver<Object>(Functions.emptyConsumer(), Functions.emptyConsumer(), Functions.EMPTY_ACTION);
    Disposable d = Disposables.empty();
    mo.onSubscribe(d);
    assertFalse(mo.isDisposed());
    mo.dispose();
    assertTrue(mo.isDisposed());
    assertTrue(d.isDisposed());
}