diff --git a/tests/regressiontests/middleware/tests.py b/tests/regressiontests/middleware/tests.py
index b8cffd9c92..e3d8350da6 100644
--- a/tests/regressiontests/middleware/tests.py
+++ b/tests/regressiontests/middleware/tests.py
@@ -20,17 +20,6 @@ from django.utils.six.moves import xrange
 
 
 class CommonMiddlewareTest(TestCase):
-    def setUp(self):
-        self.append_slash = settings.APPEND_SLASH
-        self.prepend_www = settings.PREPEND_WWW
-        self.ignorable_404_urls = settings.IGNORABLE_404_URLS
-        self.send_broken_email_links = settings.SEND_BROKEN_LINK_EMAILS
-
-    def tearDown(self):
-        settings.APPEND_SLASH = self.append_slash
-        settings.PREPEND_WWW = self.prepend_www
-        settings.IGNORABLE_404_URLS = self.ignorable_404_urls
-        settings.SEND_BROKEN_LINK_EMAILS = self.send_broken_email_links
 
     def _get_request(self, path):
         request = HttpRequest()
@@ -41,74 +30,66 @@ class CommonMiddlewareTest(TestCase):
         request.path = request.path_info = "/middleware/%s" % path
         return request
 
+    @override_settings(APPEND_SLASH=True)
     def test_append_slash_have_slash(self):
         """
         Tests that URLs with slashes go unmolested.
         """
-        settings.APPEND_SLASH = True
         request = self._get_request('slash/')
         self.assertEqual(CommonMiddleware().process_request(request), None)
 
+    @override_settings(APPEND_SLASH=True)
     def test_append_slash_slashless_resource(self):
         """
         Tests that matches to explicit slashless URLs go unmolested.
         """
-        settings.APPEND_SLASH = True
         request = self._get_request('noslash')
         self.assertEqual(CommonMiddleware().process_request(request), None)
 
+    @override_settings(APPEND_SLASH=True)
     def test_append_slash_slashless_unknown(self):
         """
         Tests that APPEND_SLASH doesn't redirect to unknown resources.
         """
-        settings.APPEND_SLASH = True
         request = self._get_request('unknown')
         self.assertEqual(CommonMiddleware().process_request(request), None)
 
+    @override_settings(APPEND_SLASH=True)
     def test_append_slash_redirect(self):
         """
         Tests that APPEND_SLASH redirects slashless URLs to a valid pattern.
         """
-        settings.APPEND_SLASH = True
         request = self._get_request('slash')
         r = CommonMiddleware().process_request(request)
         self.assertEqual(r.status_code, 301)
         self.assertEqual(r['Location'], 'http://testserver/middleware/slash/')
 
+    @override_settings(APPEND_SLASH=True, DEBUG=True)
     def test_append_slash_no_redirect_on_POST_in_DEBUG(self):
         """
         Tests that while in debug mode, an exception is raised with a warning
         when a failed attempt is made to POST to an URL which would normally be
         redirected to a slashed version.
         """
-        settings.APPEND_SLASH = True
-        settings.DEBUG = True
         request = self._get_request('slash')
         request.method = 'POST'
-        self.assertRaises(
-            RuntimeError,
-            CommonMiddleware().process_request,
-            request)
-        try:
+        with six.assertRaisesRegex(self, RuntimeError, 'end in a slash'):
             CommonMiddleware().process_request(request)
-        except RuntimeError as e:
-            self.assertTrue('end in a slash' in str(e))
-        settings.DEBUG = False
 
+    @override_settings(APPEND_SLASH=False)
     def test_append_slash_disabled(self):
         """
         Tests disabling append slash functionality.
         """
-        settings.APPEND_SLASH = False
         request = self._get_request('slash')
         self.assertEqual(CommonMiddleware().process_request(request), None)
 
+    @override_settings(APPEND_SLASH=True)
     def test_append_slash_quoted(self):
         """
         Tests that URLs which require quoting are redirected to their slash
         version ok.
         """
-        settings.APPEND_SLASH = True
         request = self._get_request('needsquoting#')
         r = CommonMiddleware().process_request(request)
         self.assertEqual(r.status_code, 301)
@@ -116,9 +97,8 @@ class CommonMiddlewareTest(TestCase):
             r['Location'],
             'http://testserver/middleware/needsquoting%23/')
 
+    @override_settings(APPEND_SLASH=False, PREPEND_WWW=True)
     def test_prepend_www(self):
-        settings.PREPEND_WWW = True
-        settings.APPEND_SLASH = False
         request = self._get_request('path/')
         r = CommonMiddleware().process_request(request)
         self.assertEqual(r.status_code, 301)
@@ -126,18 +106,16 @@ class CommonMiddlewareTest(TestCase):
             r['Location'],
             'http://www.testserver/middleware/path/')
 
+    @override_settings(APPEND_SLASH=True, PREPEND_WWW=True)
     def test_prepend_www_append_slash_have_slash(self):
-        settings.PREPEND_WWW = True
-        settings.APPEND_SLASH = True
         request = self._get_request('slash/')
         r = CommonMiddleware().process_request(request)
         self.assertEqual(r.status_code, 301)
         self.assertEqual(r['Location'],
                           'http://www.testserver/middleware/slash/')
 
+    @override_settings(APPEND_SLASH=True, PREPEND_WWW=True)
     def test_prepend_www_append_slash_slashless(self):
-        settings.PREPEND_WWW = True
-        settings.APPEND_SLASH = True
         request = self._get_request('slash')
         r = CommonMiddleware().process_request(request)
         self.assertEqual(r.status_code, 301)
@@ -148,128 +126,117 @@ class CommonMiddlewareTest(TestCase):
     # The following tests examine expected behavior given a custom urlconf that
     # overrides the default one through the request object.
 
+    @override_settings(APPEND_SLASH=True)
     def test_append_slash_have_slash_custom_urlconf(self):
-      """
-      Tests that URLs with slashes go unmolested.
-      """
-      settings.APPEND_SLASH = True
-      request = self._get_request('customurlconf/slash/')
-      request.urlconf = 'regressiontests.middleware.extra_urls'
-      self.assertEqual(CommonMiddleware().process_request(request), None)
+        """
+        Tests that URLs with slashes go unmolested.
+        """
+        request = self._get_request('customurlconf/slash/')
+        request.urlconf = 'regressiontests.middleware.extra_urls'
+        self.assertEqual(CommonMiddleware().process_request(request), None)
 
+    @override_settings(APPEND_SLASH=True)
     def test_append_slash_slashless_resource_custom_urlconf(self):
-      """
-      Tests that matches to explicit slashless URLs go unmolested.
-      """
-      settings.APPEND_SLASH = True
-      request = self._get_request('customurlconf/noslash')
-      request.urlconf = 'regressiontests.middleware.extra_urls'
-      self.assertEqual(CommonMiddleware().process_request(request), None)
+        """
+        Tests that matches to explicit slashless URLs go unmolested.
+        """
+        request = self._get_request('customurlconf/noslash')
+        request.urlconf = 'regressiontests.middleware.extra_urls'
+        self.assertEqual(CommonMiddleware().process_request(request), None)
 
+    @override_settings(APPEND_SLASH=True)
     def test_append_slash_slashless_unknown_custom_urlconf(self):
-      """
-      Tests that APPEND_SLASH doesn't redirect to unknown resources.
-      """
-      settings.APPEND_SLASH = True
-      request = self._get_request('customurlconf/unknown')
-      request.urlconf = 'regressiontests.middleware.extra_urls'
-      self.assertEqual(CommonMiddleware().process_request(request), None)
+        """
+        Tests that APPEND_SLASH doesn't redirect to unknown resources.
+        """
+        request = self._get_request('customurlconf/unknown')
+        request.urlconf = 'regressiontests.middleware.extra_urls'
+        self.assertEqual(CommonMiddleware().process_request(request), None)
 
+    @override_settings(APPEND_SLASH=True)
     def test_append_slash_redirect_custom_urlconf(self):
-      """
-      Tests that APPEND_SLASH redirects slashless URLs to a valid pattern.
-      """
-      settings.APPEND_SLASH = True
-      request = self._get_request('customurlconf/slash')
-      request.urlconf = 'regressiontests.middleware.extra_urls'
-      r = CommonMiddleware().process_request(request)
-      self.assertFalse(r is None,
-          "CommonMiddlware failed to return APPEND_SLASH redirect using request.urlconf")
-      self.assertEqual(r.status_code, 301)
-      self.assertEqual(r['Location'], 'http://testserver/middleware/customurlconf/slash/')
+        """
+        Tests that APPEND_SLASH redirects slashless URLs to a valid pattern.
+        """
+        request = self._get_request('customurlconf/slash')
+        request.urlconf = 'regressiontests.middleware.extra_urls'
+        r = CommonMiddleware().process_request(request)
+        self.assertFalse(r is None,
+            "CommonMiddlware failed to return APPEND_SLASH redirect using request.urlconf")
+        self.assertEqual(r.status_code, 301)
+        self.assertEqual(r['Location'], 'http://testserver/middleware/customurlconf/slash/')
 
+    @override_settings(APPEND_SLASH=True, DEBUG=True)
     def test_append_slash_no_redirect_on_POST_in_DEBUG_custom_urlconf(self):
-      """
-      Tests that while in debug mode, an exception is raised with a warning
-      when a failed attempt is made to POST to an URL which would normally be
-      redirected to a slashed version.
-      """
-      settings.APPEND_SLASH = True
-      settings.DEBUG = True
-      request = self._get_request('customurlconf/slash')
-      request.urlconf = 'regressiontests.middleware.extra_urls'
-      request.method = 'POST'
-      self.assertRaises(
-          RuntimeError,
-          CommonMiddleware().process_request,
-          request)
-      try:
-          CommonMiddleware().process_request(request)
-      except RuntimeError as e:
-          self.assertTrue('end in a slash' in str(e))
-      settings.DEBUG = False
+        """
+        Tests that while in debug mode, an exception is raised with a warning
+        when a failed attempt is made to POST to an URL which would normally be
+        redirected to a slashed version.
+        """
+        request = self._get_request('customurlconf/slash')
+        request.urlconf = 'regressiontests.middleware.extra_urls'
+        request.method = 'POST'
+        with six.assertRaisesRegex(self, RuntimeError, 'end in a slash'):
+            CommonMiddleware().process_request(request)
 
+    @override_settings(APPEND_SLASH=False)
     def test_append_slash_disabled_custom_urlconf(self):
-      """
-      Tests disabling append slash functionality.
-      """
-      settings.APPEND_SLASH = False
-      request = self._get_request('customurlconf/slash')
-      request.urlconf = 'regressiontests.middleware.extra_urls'
-      self.assertEqual(CommonMiddleware().process_request(request), None)
+        """
+        Tests disabling append slash functionality.
+        """
+        request = self._get_request('customurlconf/slash')
+        request.urlconf = 'regressiontests.middleware.extra_urls'
+        self.assertEqual(CommonMiddleware().process_request(request), None)
 
+    @override_settings(APPEND_SLASH=True)
     def test_append_slash_quoted_custom_urlconf(self):
-      """
-      Tests that URLs which require quoting are redirected to their slash
-      version ok.
-      """
-      settings.APPEND_SLASH = True
-      request = self._get_request('customurlconf/needsquoting#')
-      request.urlconf = 'regressiontests.middleware.extra_urls'
-      r = CommonMiddleware().process_request(request)
-      self.assertFalse(r is None,
-          "CommonMiddlware failed to return APPEND_SLASH redirect using request.urlconf")
-      self.assertEqual(r.status_code, 301)
-      self.assertEqual(
-          r['Location'],
-          'http://testserver/middleware/customurlconf/needsquoting%23/')
+        """
+        Tests that URLs which require quoting are redirected to their slash
+        version ok.
+        """
+        request = self._get_request('customurlconf/needsquoting#')
+        request.urlconf = 'regressiontests.middleware.extra_urls'
+        r = CommonMiddleware().process_request(request)
+        self.assertFalse(r is None,
+            "CommonMiddlware failed to return APPEND_SLASH redirect using request.urlconf")
+        self.assertEqual(r.status_code, 301)
+        self.assertEqual(
+            r['Location'],
+            'http://testserver/middleware/customurlconf/needsquoting%23/')
 
+    @override_settings(APPEND_SLASH=False, PREPEND_WWW=True)
     def test_prepend_www_custom_urlconf(self):
-      settings.PREPEND_WWW = True
-      settings.APPEND_SLASH = False
-      request = self._get_request('customurlconf/path/')
-      request.urlconf = 'regressiontests.middleware.extra_urls'
-      r = CommonMiddleware().process_request(request)
-      self.assertEqual(r.status_code, 301)
-      self.assertEqual(
-          r['Location'],
-          'http://www.testserver/middleware/customurlconf/path/')
+        request = self._get_request('customurlconf/path/')
+        request.urlconf = 'regressiontests.middleware.extra_urls'
+        r = CommonMiddleware().process_request(request)
+        self.assertEqual(r.status_code, 301)
+        self.assertEqual(
+            r['Location'],
+            'http://www.testserver/middleware/customurlconf/path/')
 
+    @override_settings(APPEND_SLASH=True, PREPEND_WWW=True)
     def test_prepend_www_append_slash_have_slash_custom_urlconf(self):
-      settings.PREPEND_WWW = True
-      settings.APPEND_SLASH = True
-      request = self._get_request('customurlconf/slash/')
-      request.urlconf = 'regressiontests.middleware.extra_urls'
-      r = CommonMiddleware().process_request(request)
-      self.assertEqual(r.status_code, 301)
-      self.assertEqual(r['Location'],
-                        'http://www.testserver/middleware/customurlconf/slash/')
+        request = self._get_request('customurlconf/slash/')
+        request.urlconf = 'regressiontests.middleware.extra_urls'
+        r = CommonMiddleware().process_request(request)
+        self.assertEqual(r.status_code, 301)
+        self.assertEqual(r['Location'],
+                          'http://www.testserver/middleware/customurlconf/slash/')
 
+    @override_settings(APPEND_SLASH=True, PREPEND_WWW=True)
     def test_prepend_www_append_slash_slashless_custom_urlconf(self):
-      settings.PREPEND_WWW = True
-      settings.APPEND_SLASH = True
-      request = self._get_request('customurlconf/slash')
-      request.urlconf = 'regressiontests.middleware.extra_urls'
-      r = CommonMiddleware().process_request(request)
-      self.assertEqual(r.status_code, 301)
-      self.assertEqual(r['Location'],
-                        'http://www.testserver/middleware/customurlconf/slash/')
+        request = self._get_request('customurlconf/slash')
+        request.urlconf = 'regressiontests.middleware.extra_urls'
+        r = CommonMiddleware().process_request(request)
+        self.assertEqual(r.status_code, 301)
+        self.assertEqual(r['Location'],
+                          'http://www.testserver/middleware/customurlconf/slash/')
 
     # Tests for the 404 error reporting via email
 
+    @override_settings(IGNORABLE_404_URLS=(re.compile(r'foo'),),
+                       SEND_BROKEN_LINK_EMAILS = True)
     def test_404_error_reporting(self):
-        settings.IGNORABLE_404_URLS = (re.compile(r'foo'),)
-        settings.SEND_BROKEN_LINK_EMAILS = True
         request = self._get_request('regular_url/that/does/not/exist')
         request.META['HTTP_REFERER'] = '/another/url/'
         response = self.client.get(request.path)
@@ -277,17 +244,17 @@ class CommonMiddlewareTest(TestCase):
         self.assertEqual(len(mail.outbox), 1)
         self.assertIn('Broken', mail.outbox[0].subject)
 
+    @override_settings(IGNORABLE_404_URLS=(re.compile(r'foo'),),
+                       SEND_BROKEN_LINK_EMAILS = True)
     def test_404_error_reporting_no_referer(self):
-        settings.IGNORABLE_404_URLS = (re.compile(r'foo'),)
-        settings.SEND_BROKEN_LINK_EMAILS = True
         request = self._get_request('regular_url/that/does/not/exist')
         response = self.client.get(request.path)
         CommonMiddleware().process_response(request, response)
         self.assertEqual(len(mail.outbox), 0)
 
+    @override_settings(IGNORABLE_404_URLS=(re.compile(r'foo'),),
+                       SEND_BROKEN_LINK_EMAILS = True)
     def test_404_error_reporting_ignored_url(self):
-        settings.IGNORABLE_404_URLS = (re.compile(r'foo'),)
-        settings.SEND_BROKEN_LINK_EMAILS = True
         request = self._get_request('foo_url/that/does/not/exist/either')
         request.META['HTTP_REFERER'] = '/another/url/'
         response = self.client.get(request.path)
@@ -424,70 +391,66 @@ class XFrameOptionsMiddlewareTest(TestCase):
     """
     Tests for the X-Frame-Options clickjacking prevention middleware.
     """
-    def setUp(self):
-        self.x_frame_options = settings.X_FRAME_OPTIONS
-
-    def tearDown(self):
-        settings.X_FRAME_OPTIONS = self.x_frame_options
 
     def test_same_origin(self):
         """
         Tests that the X_FRAME_OPTIONS setting can be set to SAMEORIGIN to
         have the middleware use that value for the HTTP header.
         """
-        settings.X_FRAME_OPTIONS = 'SAMEORIGIN'
-        r = XFrameOptionsMiddleware().process_response(HttpRequest(),
-                                                       HttpResponse())
-        self.assertEqual(r['X-Frame-Options'], 'SAMEORIGIN')
+        with override_settings(X_FRAME_OPTIONS='SAMEORIGIN'):
+            r = XFrameOptionsMiddleware().process_response(HttpRequest(),
+                                                           HttpResponse())
+            self.assertEqual(r['X-Frame-Options'], 'SAMEORIGIN')
 
-        settings.X_FRAME_OPTIONS = 'sameorigin'
-        r = XFrameOptionsMiddleware().process_response(HttpRequest(),
+        with override_settings(X_FRAME_OPTIONS='sameorigin'):
+            r = XFrameOptionsMiddleware().process_response(HttpRequest(),
                                                        HttpResponse())
-        self.assertEqual(r['X-Frame-Options'], 'SAMEORIGIN')
+            self.assertEqual(r['X-Frame-Options'], 'SAMEORIGIN')
 
     def test_deny(self):
         """
         Tests that the X_FRAME_OPTIONS setting can be set to DENY to
         have the middleware use that value for the HTTP header.
         """
-        settings.X_FRAME_OPTIONS = 'DENY'
-        r = XFrameOptionsMiddleware().process_response(HttpRequest(),
-                                                       HttpResponse())
-        self.assertEqual(r['X-Frame-Options'], 'DENY')
+        with override_settings(X_FRAME_OPTIONS='DENY'):
+            r = XFrameOptionsMiddleware().process_response(HttpRequest(),
+                                                           HttpResponse())
+            self.assertEqual(r['X-Frame-Options'], 'DENY')
 
-        settings.X_FRAME_OPTIONS = 'deny'
-        r = XFrameOptionsMiddleware().process_response(HttpRequest(),
-                                                       HttpResponse())
-        self.assertEqual(r['X-Frame-Options'], 'DENY')
+        with override_settings(X_FRAME_OPTIONS='deny'):
+            r = XFrameOptionsMiddleware().process_response(HttpRequest(),
+                                                           HttpResponse())
+            self.assertEqual(r['X-Frame-Options'], 'DENY')
 
     def test_defaults_sameorigin(self):
         """
         Tests that if the X_FRAME_OPTIONS setting is not set then it defaults
         to SAMEORIGIN.
         """
-        del settings.X_FRAME_OPTIONS
-        r = XFrameOptionsMiddleware().process_response(HttpRequest(),
-                                                       HttpResponse())
-        self.assertEqual(r['X-Frame-Options'], 'SAMEORIGIN')
+        with override_settings(X_FRAME_OPTIONS=None):
+            del settings.X_FRAME_OPTIONS    # restored by override_settings
+            r = XFrameOptionsMiddleware().process_response(HttpRequest(),
+                                                           HttpResponse())
+            self.assertEqual(r['X-Frame-Options'], 'SAMEORIGIN')
 
     def test_dont_set_if_set(self):
         """
         Tests that if the X-Frame-Options header is already set then the
         middleware does not attempt to override it.
         """
-        settings.X_FRAME_OPTIONS = 'DENY'
-        response = HttpResponse()
-        response['X-Frame-Options'] = 'SAMEORIGIN'
-        r = XFrameOptionsMiddleware().process_response(HttpRequest(),
-                                                       response)
-        self.assertEqual(r['X-Frame-Options'], 'SAMEORIGIN')
+        with override_settings(X_FRAME_OPTIONS='DENY'):
+            response = HttpResponse()
+            response['X-Frame-Options'] = 'SAMEORIGIN'
+            r = XFrameOptionsMiddleware().process_response(HttpRequest(),
+                                                           response)
+            self.assertEqual(r['X-Frame-Options'], 'SAMEORIGIN')
 
-        settings.X_FRAME_OPTIONS = 'SAMEORIGIN'
-        response = HttpResponse()
-        response['X-Frame-Options'] = 'DENY'
-        r = XFrameOptionsMiddleware().process_response(HttpRequest(),
-                                                       response)
-        self.assertEqual(r['X-Frame-Options'], 'DENY')
+        with override_settings(X_FRAME_OPTIONS='SAMEORIGIN'):
+            response = HttpResponse()
+            response['X-Frame-Options'] = 'DENY'
+            r = XFrameOptionsMiddleware().process_response(HttpRequest(),
+                                                           response)
+            self.assertEqual(r['X-Frame-Options'], 'DENY')
 
     def test_response_exempt(self):
         """
@@ -495,18 +458,18 @@ class XFrameOptionsMiddlewareTest(TestCase):
         to False then it still sets the header, but if it's set to True then
         it does not.
         """
-        settings.X_FRAME_OPTIONS = 'SAMEORIGIN'
-        response = HttpResponse()
-        response.xframe_options_exempt = False
-        r = XFrameOptionsMiddleware().process_response(HttpRequest(),
-                                                       response)
-        self.assertEqual(r['X-Frame-Options'], 'SAMEORIGIN')
+        with override_settings(X_FRAME_OPTIONS='SAMEORIGIN'):
+            response = HttpResponse()
+            response.xframe_options_exempt = False
+            r = XFrameOptionsMiddleware().process_response(HttpRequest(),
+                                                           response)
+            self.assertEqual(r['X-Frame-Options'], 'SAMEORIGIN')
 
-        response = HttpResponse()
-        response.xframe_options_exempt = True
-        r = XFrameOptionsMiddleware().process_response(HttpRequest(),
-                                                       response)
-        self.assertEqual(r.get('X-Frame-Options', None), None)
+            response = HttpResponse()
+            response.xframe_options_exempt = True
+            r = XFrameOptionsMiddleware().process_response(HttpRequest(),
+                                                           response)
+            self.assertEqual(r.get('X-Frame-Options', None), None)
 
     def test_is_extendable(self):
         """
@@ -523,23 +486,23 @@ class XFrameOptionsMiddlewareTest(TestCase):
                     return 'SAMEORIGIN'
                 return 'DENY'
 
-        settings.X_FRAME_OPTIONS = 'DENY'
-        response = HttpResponse()
-        response.sameorigin = True
-        r = OtherXFrameOptionsMiddleware().process_response(HttpRequest(),
-                                                            response)
-        self.assertEqual(r['X-Frame-Options'], 'SAMEORIGIN')
+        with override_settings(X_FRAME_OPTIONS='DENY'):
+            response = HttpResponse()
+            response.sameorigin = True
+            r = OtherXFrameOptionsMiddleware().process_response(HttpRequest(),
+                                                                response)
+            self.assertEqual(r['X-Frame-Options'], 'SAMEORIGIN')
 
-        request = HttpRequest()
-        request.sameorigin = True
-        r = OtherXFrameOptionsMiddleware().process_response(request,
-                                                            HttpResponse())
-        self.assertEqual(r['X-Frame-Options'], 'SAMEORIGIN')
+            request = HttpRequest()
+            request.sameorigin = True
+            r = OtherXFrameOptionsMiddleware().process_response(request,
+                                                                HttpResponse())
+            self.assertEqual(r['X-Frame-Options'], 'SAMEORIGIN')
 
-        settings.X_FRAME_OPTIONS = 'SAMEORIGIN'
-        r = OtherXFrameOptionsMiddleware().process_response(HttpRequest(),
-                                                       HttpResponse())
-        self.assertEqual(r['X-Frame-Options'], 'DENY')
+        with override_settings(X_FRAME_OPTIONS='SAMEORIGIN'):
+            r = OtherXFrameOptionsMiddleware().process_response(HttpRequest(),
+                                                                HttpResponse())
+            self.assertEqual(r['X-Frame-Options'], 'DENY')
 
 
 class GZipMiddlewareTest(TestCase):