itingHost.innerHTML;
    test(t2 => {
      const ret = contentDocument.execCommand("undo");
      if (curTest.expectedUndoResult !== undefined) {
        if (typeof curTest.expectedUndoResult == "string") {
          assert_equals(
            editingHost.innerHTML,
            curTest.expectedUndoResult,
            `${t2.name}: should restore the innerHTML value`
          );
        } else {
          assert_in_array(
            editingHost.innerHTML,
            curTest.expectedUndoResult,
           