public static void main(String[] args) {

    var dispatcher = new EventDispatcher();
    dispatcher.registerHandler(UserCreatedEvent.class, new UserCreatedEventHandler());
    dispatcher.registerHandler(UserUpdatedEvent.class, new UserUpdatedEventHandler());

    var user = new User("iluwatar");
    dispatcher.dispatch(new UserCreatedEvent(user));
    dispatcher.dispatch(new UserUpdatedEvent(user));
  }
@Test
  void shouldExecuteApplicationWithoutException() {
    assertDoesNotThrow(() -> App.main(new String[]{}));
  }