chromium/third_party/blink/web_tests/editing/execCommand/outdent/blockquote_on_all_selection.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>',
      '^Start!',
      '<blockquote>',
        'Hello<br>',
        'World<br>',
        'Goodbye<br>',
      '</blockquote>|',
    '</div>',
  ],
  'Outdent',
  [
    '<div contenteditable>',
      '^Start!<br>',
      'Hello<br>',
      'World<br>',
      'Goodbye|<br>',
    '</div>',
  ],
  'blockquote with all selection');
</script>