diff --git a/tests/test_authentication.py b/tests/test_authentication.py
index 9784087d8..e7d2dd421 100644
--- a/tests/test_authentication.py
+++ b/tests/test_authentication.py
@@ -53,11 +53,28 @@ class MockView(APIView):
 
 
 urlpatterns = [
-    url(r'^session/$', MockView.as_view(authentication_classes=[SessionAuthentication])),
-    url(r'^basic/$', MockView.as_view(authentication_classes=[BasicAuthentication])),
-    url(r'^token/$', MockView.as_view(authentication_classes=[TokenAuthentication])),
-    url(r'^customtoken/$', MockView.as_view(authentication_classes=[CustomTokenAuthentication])),
-    url(r'^customkeywordtoken/$', MockView.as_view(authentication_classes=[CustomKeywordTokenAuthentication])),
+    url(
+        r'^session/$',
+        MockView.as_view(authentication_classes=[SessionAuthentication])
+    ),
+    url(
+        r'^basic/$',
+        MockView.as_view(authentication_classes=[BasicAuthentication])
+    ),
+    url(
+        r'^token/$',
+        MockView.as_view(authentication_classes=[TokenAuthentication])
+    ),
+    url(
+        r'^customtoken/$',
+        MockView.as_view(authentication_classes=[CustomTokenAuthentication])
+    ),
+    url(
+        r'^customkeywordtoken/$',
+        MockView.as_view(
+            authentication_classes=[CustomKeywordTokenAuthentication]
+        )
+    ),
     url(r'^auth-token/$', 'rest_framework.authtoken.views.obtain_auth_token'),
     url(r'^auth/', include('rest_framework.urls', namespace='rest_framework')),
 ]
@@ -72,22 +89,37 @@ class BasicAuthTests(TestCase):
         self.username = 'john'
         self.email = 'lennon@thebeatles.com'
         self.password = 'password'
-        self.user = User.objects.create_user(self.username, self.email, self.password)
+        self.user = User.objects.create_user(
+            self.username, self.email, self.password
+        )
 
     def test_post_form_passing_basic_auth(self):
         """Ensure POSTing json over basic auth with correct credentials passes and does not require CSRF"""
         credentials = ('%s:%s' % (self.username, self.password))
-        base64_credentials = base64.b64encode(credentials.encode(HTTP_HEADER_ENCODING)).decode(HTTP_HEADER_ENCODING)
+        base64_credentials = base64.b64encode(
+            credentials.encode(HTTP_HEADER_ENCODING)
+        ).decode(HTTP_HEADER_ENCODING)
         auth = 'Basic %s' % base64_credentials
-        response = self.csrf_client.post('/basic/', {'example': 'example'}, HTTP_AUTHORIZATION=auth)
+        response = self.csrf_client.post(
+            '/basic/',
+            {'example': 'example'},
+            HTTP_AUTHORIZATION=auth
+        )
         self.assertEqual(response.status_code, status.HTTP_200_OK)
 
     def test_post_json_passing_basic_auth(self):
         """Ensure POSTing form over basic auth with correct credentials passes and does not require CSRF"""
         credentials = ('%s:%s' % (self.username, self.password))
-        base64_credentials = base64.b64encode(credentials.encode(HTTP_HEADER_ENCODING)).decode(HTTP_HEADER_ENCODING)
+        base64_credentials = base64.b64encode(
+            credentials.encode(HTTP_HEADER_ENCODING)
+        ).decode(HTTP_HEADER_ENCODING)
         auth = 'Basic %s' % base64_credentials
-        response = self.csrf_client.post('/basic/', {'example': 'example'}, format='json', HTTP_AUTHORIZATION=auth)
+        response = self.csrf_client.post(
+            '/basic/',
+            {'example': 'example'},
+            format='json',
+            HTTP_AUTHORIZATION=auth
+        )
         self.assertEqual(response.status_code, status.HTTP_200_OK)
 
     def test_regression_handle_bad_base64_basic_auth_header(self):
@@ -95,7 +127,12 @@ class BasicAuthTests(TestCase):
         # regression test for issue in 'rest_framework.authentication.BasicAuthentication.authenticate'
         # https://github.com/tomchristie/django-rest-framework/issues/4089
         auth = 'Basic =a='
-        response = self.csrf_client.post('/basic/', {'example': 'example'}, format='json', HTTP_AUTHORIZATION=auth)
+        response = self.csrf_client.post(
+            '/basic/',
+            {'example': 'example'},
+            format='json',
+            HTTP_AUTHORIZATION=auth
+        )
         self.assertEqual(response.status_code, status.HTTP_401_UNAUTHORIZED)
 
     def test_post_form_failing_basic_auth(self):
@@ -105,7 +142,11 @@ class BasicAuthTests(TestCase):
 
     def test_post_json_failing_basic_auth(self):
         """Ensure POSTing json over basic auth without correct credentials fails"""
-        response = self.csrf_client.post('/basic/', {'example': 'example'}, format='json')
+        response = self.csrf_client.post(
+            '/basic/',
+            {'example': 'example'},
+            format='json'
+        )
         self.assertEqual(response.status_code, status.HTTP_401_UNAUTHORIZED)
         self.assertEqual(response['WWW-Authenticate'], 'Basic realm="api"')
 
@@ -120,7 +161,9 @@ class SessionAuthTests(TestCase):
         self.username = 'john'
         self.email = 'lennon@thebeatles.com'
         self.password = 'password'
-        self.user = User.objects.create_user(self.username, self.email, self.password)
+        self.user = User.objects.create_user(
+            self.username, self.email, self.password
+        )
 
     def tearDown(self):
         self.csrf_client.logout()
@@ -132,7 +175,9 @@ class SessionAuthTests(TestCase):
         cf. [#1810](https://github.com/tomchristie/django-rest-framework/pull/1810)
         """
         response = self.csrf_client.get('/auth/login/')
-        self.assertContains(response, '<label for="id_username">Username:</label>')
+        self.assertContains(
+            response, '<label for="id_username">Username:</label>'
+        )
 
     def test_post_form_session_auth_failing_csrf(self):
         """
@@ -144,18 +189,28 @@ class SessionAuthTests(TestCase):
 
     def test_post_form_session_auth_passing(self):
         """
-        Ensure POSTing form over session authentication with logged in user and CSRF token passes.
+        Ensure POSTing form over session authentication with logged in
+        user and CSRF token passes.
         """
-        self.non_csrf_client.login(username=self.username, password=self.password)
-        response = self.non_csrf_client.post('/session/', {'example': 'example'})
+        self.non_csrf_client.login(
+            username=self.username, password=self.password
+        )
+        response = self.non_csrf_client.post(
+            '/session/', {'example': 'example'}
+        )
         self.assertEqual(response.status_code, status.HTTP_200_OK)
 
     def test_put_form_session_auth_passing(self):
         """
-        Ensure PUTting form over session authentication with logged in user and CSRF token passes.
+        Ensure PUTting form over session authentication with
+        logged in user and CSRF token passes.
         """
-        self.non_csrf_client.login(username=self.username, password=self.password)
-        response = self.non_csrf_client.put('/session/', {'example': 'example'})
+        self.non_csrf_client.login(
+            username=self.username, password=self.password
+        )
+        response = self.non_csrf_client.put(
+            '/session/', {'example': 'example'}
+        )
         self.assertEqual(response.status_code, status.HTTP_200_OK)
 
     def test_post_form_session_auth_failing(self):
@@ -178,52 +233,81 @@ class BaseTokenAuthTests(object):
         self.username = 'john'
         self.email = 'lennon@thebeatles.com'
         self.password = 'password'
-        self.user = User.objects.create_user(self.username, self.email, self.password)
+        self.user = User.objects.create_user(
+            self.username, self.email, self.password
+        )
 
         self.key = 'abcd1234'
         self.token = self.model.objects.create(key=self.key, user=self.user)
 
     def test_post_form_passing_token_auth(self):
-        """Ensure POSTing json over token auth with correct credentials passes and does not require CSRF"""
+        """
+        Ensure POSTing json over token auth with correct
+        credentials passes and does not require CSRF
+        """
         auth = self.header_prefix + self.key
-        response = self.csrf_client.post(self.path, {'example': 'example'}, HTTP_AUTHORIZATION=auth)
+        response = self.csrf_client.post(
+            self.path, {'example': 'example'}, HTTP_AUTHORIZATION=auth
+        )
         self.assertEqual(response.status_code, status.HTTP_200_OK)
 
     def test_fail_post_form_passing_nonexistent_token_auth(self):
         # use a nonexistent token key
         auth = self.header_prefix + 'wxyz6789'
-        response = self.csrf_client.post(self.path, {'example': 'example'}, HTTP_AUTHORIZATION=auth)
+        response = self.csrf_client.post(
+            self.path, {'example': 'example'}, HTTP_AUTHORIZATION=auth
+        )
         self.assertEqual(response.status_code, status.HTTP_401_UNAUTHORIZED)
 
     def test_fail_post_form_passing_invalid_token_auth(self):
         # add an 'invalid' unicode character
         auth = self.header_prefix + self.key + "¸"
-        response = self.csrf_client.post(self.path, {'example': 'example'}, HTTP_AUTHORIZATION=auth)
+        response = self.csrf_client.post(
+            self.path, {'example': 'example'}, HTTP_AUTHORIZATION=auth
+        )
         self.assertEqual(response.status_code, status.HTTP_401_UNAUTHORIZED)
 
     def test_post_json_passing_token_auth(self):
-        """Ensure POSTing form over token auth with correct credentials passes and does not require CSRF"""
+        """
+        Ensure POSTing form over token auth with correct
+        credentials passes and does not require CSRF
+        """
         auth = self.header_prefix + self.key
-        response = self.csrf_client.post(self.path, {'example': 'example'}, format='json', HTTP_AUTHORIZATION=auth)
+        response = self.csrf_client.post(
+            self.path, {'example': 'example'},
+            format='json', HTTP_AUTHORIZATION=auth
+        )
         self.assertEqual(response.status_code, status.HTTP_200_OK)
 
     def test_post_json_makes_one_db_query(self):
-        """Ensure that authenticating a user using a token performs only one DB query"""
+        """
+        Ensure that authenticating a user using a
+        token performs only one DB query
+        """
         auth = self.header_prefix + self.key
 
         def func_to_test():
-            return self.csrf_client.post(self.path, {'example': 'example'}, format='json', HTTP_AUTHORIZATION=auth)
+            return self.csrf_client.post(
+                self.path, {'example': 'example'},
+                format='json', HTTP_AUTHORIZATION=auth
+            )
 
         self.assertNumQueries(1, func_to_test)
 
     def test_post_form_failing_token_auth(self):
-        """Ensure POSTing form over token auth without correct credentials fails"""
+        """
+        Ensure POSTing form over token auth without correct credentials fails
+        """
         response = self.csrf_client.post(self.path, {'example': 'example'})
         self.assertEqual(response.status_code, status.HTTP_401_UNAUTHORIZED)
 
     def test_post_json_failing_token_auth(self):
-        """Ensure POSTing json over token auth without correct credentials fails"""
-        response = self.csrf_client.post(self.path, {'example': 'example'}, format='json')
+        """
+        Ensure POSTing json over token auth without correct credentials fails
+        """
+        response = self.csrf_client.post(
+            self.path, {'example': 'example'}, format='json'
+        )
         self.assertEqual(response.status_code, status.HTTP_401_UNAUTHORIZED)
 
 
@@ -246,16 +330,25 @@ class TokenAuthTests(BaseTokenAuthTests, TestCase):
     def test_token_login_json(self):
         """Ensure token login view using JSON POST works."""
         client = APIClient(enforce_csrf_checks=True)
-        response = client.post('/auth-token/',
-                               {'username': self.username, 'password': self.password}, format='json')
+        response = client.post(
+            '/auth-token/',
+            {'username': self.username, 'password': self.password},
+            format='json'
+        )
         self.assertEqual(response.status_code, status.HTTP_200_OK)
         self.assertEqual(response.data['token'], self.key)
 
     def test_token_login_json_bad_creds(self):
-        """Ensure token login view using JSON POST fails if bad credentials are used."""
+        """
+        Ensure token login view using JSON POST fails if
+        bad credentials are used
+        """
         client = APIClient(enforce_csrf_checks=True)
-        response = client.post('/auth-token/',
-                               {'username': self.username, 'password': "badpass"}, format='json')
+        response = client.post(
+            '/auth-token/',
+            {'username': self.username, 'password': "badpass"},
+            format='json'
+        )
         self.assertEqual(response.status_code, 400)
 
     def test_token_login_json_missing_fields(self):