<t:root xmlns:t="test"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="test test.xsd">

  <a>abc</a>
  <a>&#x1FFF;&#xD7FF;</a>
  <a>&#x10000;&#x10FFFD;</a>

  <b>abc</b>
  <b>a&#x1FFF;&#xD7FF;c</b>
  <b>&#x10000;&#x10FFFD;bc</b>
  <b>ab&#x10000;&#x10FFFD;</b>

</t:root>
