mozilla-release/layout/reftests/text-decoration/underline-table-caption-standards-ref.html

<!DOCTYPE HTML>
<title>text-decoration: underline test</title>
<table border>
  <caption><span style="text-decoration: underline">This is the table caption</span></caption>
  <tr>
    <td>Row 1, Cell 1</td>
    <td>Row 1, Cell 2</td>
  </tr>
  <tr>
    <td>Row 2, Cell 1</td>
    <td>Row 2, Cell 2</td>
  </tr>
</table>