asses if there is no red visible on the page.</p>
        <table>
            <tr id="collapsing1">
                <td></td>
            </tr>
            <tr>
               <td id="test"></td>
            </tr>
            <tr id="collapsing2">
                <td></td>
            </tr>
        </table>
    </body>
</html>