de, delegatesFocus,
      serializable, clonable, emptyShadowTree) {
  const t = test(t => {
    // Create and attach element
    let wrapper;
    if (runGetHTMLOnShadowRoot) {
      // This ensures we're testing both Element.getHTML() and ShadowRoot.getHTML().
      const host = document.createElement('div');
      t.add_cleanup(function() { host.remove(); });
      document.body.appendChild(host);
      wrapper = host.attachShadow({mode: 'open'});
    } else {
      wrapper = document.createElement('div')