tListener("load", resolve, {once: true});
  });
}, "Waiting for load...");

/**
 * This test does NOT test whether the edit result is valid or invalid.
 * This test just tests whether "undo" and "redo" restores previous state
 * and additional "undo" and "redo" does not run unexpectedly.
 *
 * description: Set string to explain what's testing.
 * editorInnerHTML: Set initial innerHTML value of editor.
 * init: Set a function object if you need to test complicated cases, e.g.,
 *       testing with empty tex