This test expects an error to be raised when evaluating the input port "source".  However, since the result is input to a p:sink, it need never be evaluated.

      <p:sink>
        <p:input port="source" select="//para/text()">
          <p:inline>
            <doc>
              <para>some text</para>
            </doc>
          </p:inline>
        </p:input>
      </p:sink>