Assertion: A :lang value will not match an xml:lang attribute value when the former contains more subtags.

Notes:
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. If :lang does not work with xml:lang, the test should show a message "Ignore this test." You should ignore the instructions and test results that follow and mark the results as "not applicable".