[1.7.x] Fixed #22254 -- Noted the requirement of calling django.setup() when running

Thanks Peter Landry for the report.

Backport of 26b03f2526 from master

docs/topics/testing/advanced.txt

@@ -251,6 +251,11 @@ automatically as part of the setup of ``./manage.py test``. You only
 need to manually invoke this method if you're not using running your
 tests via Django's test runner.
 
+.. versionchanged:: 1.7
+
+If you are not using a management command to invoke the tests, you will also
+need to first setup Django itself using :func:`django.setup()`.
+
 .. _other-testing-frameworks:
 
 Using different testing frameworks