testButtonAfterEnterDocument() {
    const node = dom.getElement('demoMenuButton');
    menuButton.decorate(node);

    menuButton.exitDocument();
    menuButton.enterDocument();

    testingEvents.fireClickSequence(node);
    assertTrue('Menu must open after click', menuButton.isOpen());

    const menuItem2 = dom.getElement('menuItem2');
    testingEvents.fireClickSequence(menuItem2);
    assertFalse('Menu must close on clicking when open', menuButton.isOpen());
  }
Open the menu and click on the menu item inside after exiting and entering
the document once, to test proper setup/teardown behavior of MenuButton.