Test nw-err-xs0006-001

The pipeline

<p:declare-step xmlns:err="http://www.w3.org/ns/xproc-error"
                xmlns:ex="http://test" xmlns:p="http://www.w3.org/ns/xproc"
                xmlns:t="http://xproc.org/ns/testsuite/3.0" version="3.0">
   <p:output port="result"/>
   <p:declare-step type="ex:not-primary">
      <p:output port="result" primary="false"/>
      <p:identity>
         <p:with-input>
            <doc/>
         </p:with-input>
      </p:identity>
   </p:declare-step>
   <ex:not-primary/>
</p:declare-step>