Tests XS0052 is raised on import of non existing resource.
Test ab-import-002.xml is expected to fail with error code err:XS0052.
<p:declare-step xmlns:err="http://www.w3.org/ns/xproc-error" xmlns:p="http://www.w3.org/ns/xproc" xmlns:x="http://test" version="3.0">
   <p:import href="i-do-not-exist.xpl">
   <p:output port="result">
   <x:step/>
</p:declare-step>
Added new tests for p:declare-step and p:import.