Enabled SimpleTestCase to be decorated by override_settings

Refs #18417. Also fixed some test case classes which subclassed
the wrong parent.

django/test/testcases.py

@@ -241,6 +241,40 @@ class _AssertTemplateNotUsedContext(_AssertTemplateUsedContext):
 
 
 class SimpleTestCase(ut2.TestCase):
+    def __call__(self, result=None):
+        """
+        Wrapper around default __call__ method to perform common Django test
+        set up. This means that user-defined Test Cases aren't required to
+        include a call to super().setUp().
+        """
+        testMethod = getattr(self, self._testMethodName)
+        skipped = (getattr(self.__class__, "__unittest_skip__", False) or
+            getattr(testMethod, "__unittest_skip__", False))
+
+        if not skipped:
+            try:
+                self._pre_setup()
+            except (KeyboardInterrupt, SystemExit):
+                raise
+            except Exception:
+                result.addError(self, sys.exc_info())
+                return
+        super(SimpleTestCase, self).__call__(result)
+        if not skipped:
+            try:
+                self._post_teardown()
+            except (KeyboardInterrupt, SystemExit):
+                raise
+            except Exception:
+                result.addError(self, sys.exc_info())
+                return
+
+    def _pre_setup(self):
+        pass
+
+    def _post_teardown(self):
+        pass
+
     def save_warnings_state(self):
         """
         Saves the state of the warnings module
@@ -412,6 +446,7 @@ class TransactionTestCase(SimpleTestCase):
               ROOT_URLCONF with it.
             * Clearing the mail test outbox.
         """
+        self.client = self.client_class()
         self._fixture_setup()
         self._urlconf_setup()
         mail.outbox = []
@@ -459,35 +494,6 @@ class TransactionTestCase(SimpleTestCase):
             settings.ROOT_URLCONF = self.urls
             clear_url_caches()
 
-    def __call__(self, result=None):
-        """
-        Wrapper around default __call__ method to perform common Django test
-        set up. This means that user-defined Test Cases aren't required to
-        include a call to super().setUp().
-        """
-        testMethod = getattr(self, self._testMethodName)
-        skipped = (getattr(self.__class__, "__unittest_skip__", False) or
-            getattr(testMethod, "__unittest_skip__", False))
-
-        if not skipped:
-            self.client = self.client_class()
-            try:
-                self._pre_setup()
-            except (KeyboardInterrupt, SystemExit):
-                raise
-            except Exception:
-                result.addError(self, sys.exc_info())
-                return
-        super(TransactionTestCase, self).__call__(result)
-        if not skipped:
-            try:
-                self._post_teardown()
-            except (KeyboardInterrupt, SystemExit):
-                raise
-            except Exception:
-                result.addError(self, sys.exc_info())
-                return
-
     def _post_teardown(self):
         """ Performs any post-test things. This includes:
 

django/test/utils.py

@@ -187,11 +187,11 @@ class override_settings(object):
         self.disable()
 
     def __call__(self, test_func):
-        from django.test import TransactionTestCase
+        from django.test import SimpleTestCase
         if isinstance(test_func, type):
-            if not issubclass(test_func, TransactionTestCase):
+            if not issubclass(test_func, SimpleTestCase):
                 raise Exception(
-                    "Only subclasses of Django TransactionTestCase can be decorated "
+                    "Only subclasses of Django SimpleTestCase can be decorated "
                     "with override_settings")
             original_pre_setup = test_func._pre_setup
             original_post_teardown = test_func._post_teardown