essage';

  assert_throws_dom('NotFoundError', () => {
    control.i.setValidity(flags, m, document.body);
  }, 'Not a descendant');

  let notHTMLElement = document.createElementNS('some-random-namespace', 'foo');
  control.appendChild(notHTMLElement);
  assert_throws_js(TypeError, () => {
    control.i.setValidity(flags, m, notHTMLElement);
  }, 'Not a HTMLElement');
  notHTMLElement.remove();

  // A descendant
  control.i.setValidity(flags, m, control.querySelector('light-child'));

  // An element in t