chromium/third_party/blink/web_tests/editing/selection/extend-by-sentence-001.html

<!doctype html>
<script src="../../resources/testharness.js"></script>
<script src="../../resources/testharnessreport.js"></script>
<script src="../assert_selection.js"></script>
<script>
selection_test(
  [
    '<div contenteditable>',
      '<frijole style="display:block;">one two three</frijole>',
      '<doodad style="display:block;">four| five six</doodad>',
    '</div>',
  ],
  selection => selection.modify('move', 'backward', 'sentence'),
  [
    '<div contenteditable>',
      '<frijole style="display:block;">one two three</frijole>',
      '<doodad style="display:block;">|four five six</doodad>',
    '</div>',
  ],
  '1 move backward sentence');

selection_test(
  [
    '<div contenteditable>',
      '<frijole style="display:block;">one two three</frijole>',
      '<doodad style="display:block;">|four five six</doodad>',
    '</div>',
  ],
  selection => selection.modify('extend', 'forward', 'sentence'),
  [
    '<div contenteditable>',
      '<frijole style="display:block;">one two three</frijole>',
      '<doodad style="display:block;">^four five six|</doodad>',
    '</div>',
  ],
  '2 extend forkward sentence');
</script>