e "pre-line":
      return "preLine";
    case "nowrap":
      return "nowrap";
    default:
      return null;
  }
})();
const utils = new EditorTestUtils(editingHost);

const tests = [
  // The cases that the following line is a child of parent block whose
  // white-space is normal.
  {
    initialHTML:
      `<div style="${leftWhiteSpace}">abc${caretInLeft}</div>` +
        `${caretInRight}def`,
    expectedHTML: aAttrsInLeftBlock => {
      return [
        `<div style="${leftWhiteSpace}">abc<span ${aA