// check listener is notify only one time.
Sleeper.SECONDS.sleep(2);
assertThat(listenerSpy.getNotifyCount()).isEqualTo(1);
widget.removeActionListener(listenerSpy);
listenerSpy.reset();
tth.click(button);
Sleeper.SECONDS.sleep(3);
assertThat(listenerSpy.getNotifyCount()).isZero();