Fixed #21281 -- Made override_settings act at class level when used as a TestCase decorator.

docs/releases/1.8.txt

@@ -919,3 +919,11 @@ to construct the "view on site" URL. This URL is now accessible using the
 ``FormMixin`` subclasses that override the ``get_form()`` method should make
 sure to provide a default value for the ``form_class`` argument since it's
 now optional.
+
+Overriding ``setUpClass`` / ``tearDownClass`` in test cases
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The decorators :func:`~django.test.override_settings` and
+:func:`~django.test.modify_settings` now act at the class level when used as
+class decorators. As a consequence, when overriding ``setUpClass()`` or
+``tearDownClass()``, the ``super`` implementation should always be called.

docs/topics/testing/tools.txt

@@ -607,6 +607,25 @@ then you should use :class:`~django.test.TransactionTestCase` or
 
 ``SimpleTestCase`` inherits from ``unittest.TestCase``.
 
+.. warning::
+
+    ``SimpleTestCase`` and its subclasses (e.g. ``TestCase``, ...) rely on
+    ``setUpClass()`` and ``tearDownClass()`` to perform some class-wide
+    initialization (e.g. overriding settings). If you need to override those
+    methods, don't forget to call the ``super`` implementation::
+
+        class MyTestCase(TestCase):
+
+            @classmethod
+            def setUpClass(cls):
+                super(cls, MyTestCase).setUpClass()     # Call parent first
+                ...
+
+            @classmethod
+            def tearDownClass(cls):
+                ...
+                super(cls, MyTestCase).tearDownClass()  # Call parent last
+
 TransactionTestCase
 ~~~~~~~~~~~~~~~~~~~
 
@@ -751,8 +770,8 @@ Then, add a ``LiveServerTestCase``-based test to your app's tests module
 
         @classmethod
         def setUpClass(cls):
-            cls.selenium = WebDriver()
             super(MySeleniumTests, cls).setUpClass()
+            cls.selenium = WebDriver()
 
         @classmethod
         def tearDownClass(cls):