  constructor() { super(); return w.document.implementation.createHTMLDocument().createElement('div'); }
      });
    });
  }, `${description}6.1.7. If result\'s node document is not document, then throw a NotSupportedError`);

  /* This is not testsable today, see https://github.com/whatwg/html/issues/1402
  test_with_window((w) => {
    assert_throws(expectNotSupportedError, () => {
      define_and_create_element(w, class extends w.HTMLElement {
        constructor() { super(); return w.document.createE