chromium/third_party/blink/web_tests/editing/pasteboard/copy-paste-underlined.html

<!doctype html>
<script src="../../resources/testharness.js"></script>
<script src="../../resources/testharnessreport.js"></script>
<script src="../assert_selection.js"></script>
<script>
test(() => {
  assert_not_equals(
      window.testRunner, undefined,
     'This test requires testRunner.');

  assert_selection(
      [
        '<div contenteditable>^foo bar baz.|</div>',
        '<div contenteditable id="paste"><br></div>'
      ].join(''),
      selection => {
        const document = selection.document;
        document.execCommand('underline');
        document.execCommand('copy');
        document.getElementById('paste').focus();
        document.execCommand('paste');
      },
      [
        '<div contenteditable><u>foo bar baz.</u></div>',
        '<div contenteditable id="paste"><u>foo bar baz.|</u></div>'
      ].join(''));
  }, 'Copy/paste underlined text.');

test(() => {
  assert_not_equals(
      window.testRunner, undefined,
     'This test requires testRunner.');

  assert_selection(
      [
        '<div contenteditable spellcheck="false">^foo bar baz.|</div>',
        '<div contenteditable id="paste"><br></div>'
      ].join(''),
      selection => {
        const document = selection.document;
        document.execCommand('underline');
        document.execCommand('copy');
        document.getElementById('paste').focus();
        document.execCommand('paste');
      },
      [
        '<div contenteditable spellcheck="false"><u>foo bar baz.</u></div>',
        '<div contenteditable id="paste"><u>foo bar baz.|</u></div>'
      ].join(''));
  }, 'Copy/paste underlined text with spell checker off.');
</script>