This test uses an implicitly declared parameter:

<param name="sales-collection-uri" as="xs:string" select="'http://www.w3.org/2010/09/qt-fots-catalog/sales-json'" declared="false"/>

But the query starts with a namespace declaration, so it is not easy for a test driver to insert an external variable declaration into the text of the query at a suitable point.

The test catalog schema (but not the user guide) documents a mechanism to cope with this: it says the string (:VARDECL:) can be placed in the query at the point where the external variable is to be declared. But there are no tests that actually use this mechanism and there are probably many test drivers that don't recognize it. It would be much easier since this is an XQuery-only test to simply add the external variable declaration to the query, and change the parameter to say declared="true".