chromium/third_party/blink/web_tests/editing/spelling/grammar-edit-word.html

<!DOCTYPE html>
<script src="../../resources/testharness.js"></script>
<script src="../../resources/testharnessreport.js"></script>
<script src="../assert_selection.js"></script>
<script src="spellcheck_test.js"></script>
<script>
spellcheck_test(
    '<div contenteditable>You has the right.|</div>',
    '',
    '<div contenteditable>You ~has~ the right.</div>',
    {
      title: 'Has marker on ungrammatical initial text',
      callback: sample => spellcheck_test(
          sample,
          (document, testRunner) => {
            // Delete the end of this sentence until it becomes 'You ha'.
            for (let i = 0; i < 12; ++i)
              testRunner.execCommand('DeleteBackward');
          },
          '<div contenteditable>You ha</div>',
          'Remove grammar markers when editing a grammatically-incorrect word.')
    });
</script>