lang(es), xml:lang="mx-es"
Ignore this test. (:lang with xml:lang is not supported)
You can only get meaningful results for this test if :lang works with xml:lang, since it checks a detail with regard to that support.
Test passes if you see green below.
Assertion: When the :lang value uses a single subtag, it will not match against an xml:lang attribute value where that value appears in a different position.