Refs #17876: enhanced new test to actually test underlying function, not just...

Refs #17876: enhanced new test to actually test underlying function, not just ensure trying to use it does not raise an exception. Thanks Przemek Lewandowski.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@17695 bcc190cf-cafb-0310-a4f2-bffc1f526a37