Tests an error to be raised if match on p:add-attribute matches attribute.
Test ab-add-attribute-021.xml is expected to fail with error code err:XC0023 [Core steps, XProc]
.
<p:declare-step xmlns:err="http://www.w3.org/ns/xproc-error" xmlns:p="http://www.w3.org/ns/xproc" version="3.0">
<p:output port="result"/>
<p:add-attribute match="/doc/@attribute" attribute-value="5" attribute-name="att">
<p:with-input>
<doc attribute="3">
Some text
<!-- a comment -->
<?pi?>
</doc>
</p:with-input>
</p:add-attribute>
</p:declare-step>
Added new tests for p:add-attribute.