With all the old joysticks and joypads we have in classic Amigas is hard to know if they are still working correctly. Joytest let you know if the Amiga notices the button push or if the button it's not working. It's CD32 compatible, so you can test CD32 gamepads too. I've included the source code in Blitz Basic (it uses few code lines).
More info here: /zener/works/joytest/joytest.lha