t node.
 * run: Set a function object which run something modifying the editor (or
 *      does nothing).
 * expectedUndoResult: Set an expected innerHTML result as string or array
 *                     of the string.  If this is not specified, it's compared
 *                     with editorInnerHTML value.
 * cleanUp: Set a function object if you need to clean something up after the
 *          test.
 */

const tests = [
  {
    description: "insertParagraph at start of a paragraph",
    editorInnerHTML: