diff --git a/django/contrib/admin/options.py b/django/contrib/admin/options.py
index ff6aa94be4..ba7e36c8c2 100644
--- a/django/contrib/admin/options.py
+++ b/django/contrib/admin/options.py
@@ -352,7 +352,7 @@ class BaseModelAdmin(metaclass=forms.MediaDefiningClass):
             try:
                 field = model._meta.get_field(part)
             except FieldDoesNotExist:
-                # Lookups on non-existent fields are ok, since they're ignored
+                # Lookups on nonexistent fields are ok, since they're ignored
                 # later.
                 break
             # It is allowed to filter on values that would be found from local
diff --git a/django/contrib/auth/backends.py b/django/contrib/auth/backends.py
index e0fbd21b38..64f9af38ba 100644
--- a/django/contrib/auth/backends.py
+++ b/django/contrib/auth/backends.py
@@ -16,7 +16,7 @@ class ModelBackend:
             user = UserModel._default_manager.get_by_natural_key(username)
         except UserModel.DoesNotExist:
             # Run the default password hasher once to reduce the timing
-            # difference between an existing and a non-existing user (#20760).
+            # difference between an existing and a nonexistent user (#20760).
             UserModel().set_password(password)
         else:
             if user.check_password(password) and self.user_can_authenticate(user):
diff --git a/django/contrib/contenttypes/fields.py b/django/contrib/contenttypes/fields.py
index c2b46d1254..df6113f462 100644
--- a/django/contrib/contenttypes/fields.py
+++ b/django/contrib/contenttypes/fields.py
@@ -97,7 +97,8 @@ class GenericForeignKey:
         except FieldDoesNotExist:
             return [
                 checks.Error(
-                    "The GenericForeignKey object ID references the non-existent field '%s'." % self.fk_field,
+                    "The GenericForeignKey object ID references the "
+                    "nonexistent field '%s'." % self.fk_field,
                     obj=self,
                     id='contenttypes.E001',
                 )
@@ -115,7 +116,8 @@ class GenericForeignKey:
         except FieldDoesNotExist:
             return [
                 checks.Error(
-                    "The GenericForeignKey content type references the non-existent field '%s.%s'." % (
+                    "The GenericForeignKey content type references the "
+                    "nonexistent field '%s.%s'." % (
                         self.model._meta.object_name, self.ct_field
                     ),
                     obj=self,
diff --git a/django/core/cache/backends/memcached.py b/django/core/cache/backends/memcached.py
index 6be2378e56..8f87f487bf 100644
--- a/django/core/cache/backends/memcached.py
+++ b/django/core/cache/backends/memcached.py
@@ -108,7 +108,7 @@ class BaseMemcachedCache(BaseCache):
         try:
             val = self._cache.incr(key, delta)
 
-        # python-memcache responds to incr on non-existent keys by
+        # python-memcache responds to incr on nonexistent keys by
         # raising a ValueError, pylibmc by raising a pylibmc.NotFound
         # and Cmemcache returns None. In all cases,
         # we should raise a ValueError though.
@@ -126,7 +126,7 @@ class BaseMemcachedCache(BaseCache):
         try:
             val = self._cache.decr(key, delta)
 
-        # python-memcache responds to incr on non-existent keys by
+        # python-memcache responds to incr on nonexistent keys by
         # raising a ValueError, pylibmc by raising a pylibmc.NotFound
         # and Cmemcache returns None. In all cases,
         # we should raise a ValueError though.
diff --git a/django/db/models/base.py b/django/db/models/base.py
index 497a18f51a..2914ba2a6f 100644
--- a/django/db/models/base.py
+++ b/django/db/models/base.py
@@ -1497,7 +1497,7 @@ class Model(metaclass=ModelBase):
             except KeyError:
                 errors.append(
                     checks.Error(
-                        "'%s' refers to the non-existent field '%s'." % (
+                        "'%s' refers to the nonexistent field '%s'." % (
                             option, field_name,
                         ),
                         obj=cls,
@@ -1570,7 +1570,7 @@ class Model(metaclass=ModelBase):
         # but is an alias and therefore won't be found by opts.get_field.
         fields = {f for f in fields if f != 'pk'}
 
-        # Check for invalid or non-existent fields in ordering.
+        # Check for invalid or nonexistent fields in ordering.
         invalid_fields = []
 
         # Any field name that is not present in field_names does not exist.
@@ -1586,7 +1586,7 @@ class Model(metaclass=ModelBase):
         for invalid_field in invalid_fields:
             errors.append(
                 checks.Error(
-                    "'ordering' refers to the non-existent field '%s'." % invalid_field,
+                    "'ordering' refers to the nonexistent field '%s'." % invalid_field,
                     obj=cls,
                     id='models.E015',
                 )
diff --git a/django/db/models/query.py b/django/db/models/query.py
index 244cfaf164..290be2e779 100644
--- a/django/db/models/query.py
+++ b/django/db/models/query.py
@@ -1267,7 +1267,7 @@ class RawQuerySet:
                 index = columns.index(query_name)
                 columns[index] = model_name
             except ValueError:
-                # Ignore translations for non-existent column names
+                # Ignore translations for nonexistent column names
                 pass
         return columns
 
diff --git a/docs/faq/admin.txt b/docs/faq/admin.txt
index 26ad08374f..f1c6f61eba 100644
--- a/docs/faq/admin.txt
+++ b/docs/faq/admin.txt
@@ -62,7 +62,7 @@ Some objects aren't appearing in the admin.
 Inconsistent row counts may be caused by missing foreign key values or a
 foreign key field incorrectly set to :attr:`null=False
 <django.db.models.Field.null>`. If you have a record with a
-:class:`~django.db.models.ForeignKey` pointing to a non-existent object and
+:class:`~django.db.models.ForeignKey` pointing to a nonexistent object and
 that foreign key is included is
 :attr:`~django.contrib.admin.ModelAdmin.list_display`, the record will not be
 shown in the admin changelist because the Django model is declaring an
diff --git a/docs/ref/checks.txt b/docs/ref/checks.txt
index 35c0bd6987..d71219f5be 100644
--- a/docs/ref/checks.txt
+++ b/docs/ref/checks.txt
@@ -281,13 +281,13 @@ Models
 * **models.E010**: ``unique_together`` must be a list or tuple.
 * **models.E011**: All ``unique_together`` elements must be lists or tuples.
 * **models.E012**: ``index_together/unique_together`` refers to the
-  non-existent field ``<field name>``.
+  nonexistent field ``<field name>``.
 * **models.E013**: ``index_together/unique_together`` refers to a
   ``ManyToManyField`` ``<field name>``, but ``ManyToManyField``\s are not
   supported for that option.
 * **models.E014**: ``ordering`` must be a tuple or list (even if you want to
   order by only one field).
-* **models.E015**: ``ordering`` refers to the non-existent field
+* **models.E015**: ``ordering`` refers to the nonexistent field
   ``<field name>``.
 * **models.E016**: ``index_together/unique_together`` refers to field
   ``<field_name>`` which is not local to model ``<model>``.
@@ -659,9 +659,9 @@ The following checks are performed when a model contains a
 :class:`~django.contrib.contenttypes.fields.GenericRelation`:
 
 * **contenttypes.E001**: The ``GenericForeignKey`` object ID references the
-  non-existent field ``<field>``.
+  nonexistent field ``<field>``.
 * **contenttypes.E002**: The ``GenericForeignKey`` content type references the
-  non-existent field ``<field>``.
+  nonexistent field ``<field>``.
 * **contenttypes.E003**: ``<field>`` is not a ``ForeignKey``.
 * **contenttypes.E004**: ``<field>`` is not a ``ForeignKey`` to
   ``contenttypes.ContentType``.
diff --git a/docs/ref/request-response.txt b/docs/ref/request-response.txt
index 2d564d1954..6de18234c4 100644
--- a/docs/ref/request-response.txt
+++ b/docs/ref/request-response.txt
@@ -323,10 +323,10 @@ Methods
         'Tony'
         >>> request.get_signed_cookie('name', salt='name-salt')
         'Tony' # assuming cookie was set using the same salt
-        >>> request.get_signed_cookie('non-existing-cookie')
+        >>> request.get_signed_cookie('nonexistent-cookie')
         ...
-        KeyError: 'non-existing-cookie'
-        >>> request.get_signed_cookie('non-existing-cookie', False)
+        KeyError: 'nonexistent-cookie'
+        >>> request.get_signed_cookie('nonexistent-cookie', False)
         False
         >>> request.get_signed_cookie('cookie-that-was-tampered-with')
         ...
diff --git a/docs/ref/templates/api.txt b/docs/ref/templates/api.txt
index afa43f7abd..c4f250e667 100644
--- a/docs/ref/templates/api.txt
+++ b/docs/ref/templates/api.txt
@@ -381,7 +381,7 @@ replaced with the name of the invalid variable.
     idea to turn it on as a 'development default'.
 
     Many templates, including those in the Admin site, rely upon the silence
-    of the template system when a non-existent variable is encountered. If you
+    of the template system when a nonexistent variable is encountered. If you
     assign a value other than ``''`` to ``string_if_invalid``, you will
     experience rendering problems with these templates and sites.
 
diff --git a/docs/ref/utils.txt b/docs/ref/utils.txt
index 1e37d28ca8..c9ab5e3975 100644
--- a/docs/ref/utils.txt
+++ b/docs/ref/utils.txt
@@ -984,7 +984,7 @@ appropriate entities.
     ``value`` aware during a DST transition such that the time never occurred
     (when entering into DST). Setting ``is_dst`` to ``True`` or ``False`` will
     avoid the exception by moving the hour backwards or forwards by 1
-    respectively. For example, ``is_dst=True`` would change a non-existent
+    respectively. For example, ``is_dst=True`` would change a nonexistent
     time of 2:30 to 1:30 and ``is_dst=False`` would change the time to 3:30.
 
 .. function:: make_naive(value, timezone=None)
diff --git a/docs/releases/0.96.txt b/docs/releases/0.96.txt
index bbec1c3eaf..21267910c7 100644
--- a/docs/releases/0.96.txt
+++ b/docs/releases/0.96.txt
@@ -65,7 +65,7 @@ The effect of this change is that running ``manage.py reset`` and
 similar commands against an existing database may generate SQL with
 the new form of constraint name, while the database itself contains
 constraints named in the old form; this will cause the database server
-to raise an error message about modifying non-existent constraints.
+to raise an error message about modifying nonexistent constraints.
 
 If you need to work around this, there are two methods available:
 
diff --git a/tests/admin_checks/tests.py b/tests/admin_checks/tests.py
index e081caeca1..5419fc1009 100644
--- a/tests/admin_checks/tests.py
+++ b/tests/admin_checks/tests.py
@@ -344,7 +344,10 @@ class SystemChecksTestCase(SimpleTestCase):
         self.assertEqual(errors, expected)
 
     def test_generic_inline_model_admin_bad_ct_field(self):
-        "A GenericInlineModelAdmin raises problems if the ct_field points to a non-existent field."
+        """
+        A GenericInlineModelAdmin errors if the ct_field points to a
+        nonexistent field.
+        """
         class InfluenceInline(GenericStackedInline):
             model = Influence
             ct_field = 'nonexistent'
@@ -363,7 +366,10 @@ class SystemChecksTestCase(SimpleTestCase):
         self.assertEqual(errors, expected)
 
     def test_generic_inline_model_admin_bad_fk_field(self):
-        "A GenericInlineModelAdmin raises problems if the ct_fk_field points to a non-existent field."
+        """
+        A GenericInlineModelAdmin errors if the ct_fk_field points to a
+        nonexistent field.
+        """
         class InfluenceInline(GenericStackedInline):
             model = Influence
             ct_fk_field = 'nonexistent'
@@ -428,18 +434,15 @@ class SystemChecksTestCase(SimpleTestCase):
         self.assertEqual(errors, expected)
 
     def test_app_label_in_admin_checks(self):
-        """
-        Regression test for #15669 - Include app label in admin system check messages
-        """
-        class RawIdNonexistingAdmin(admin.ModelAdmin):
-            raw_id_fields = ('nonexisting',)
+        class RawIdNonexistentAdmin(admin.ModelAdmin):
+            raw_id_fields = ('nonexistent',)
 
-        errors = RawIdNonexistingAdmin(Album, AdminSite()).check()
+        errors = RawIdNonexistentAdmin(Album, AdminSite()).check()
         expected = [
             checks.Error(
-                "The value of 'raw_id_fields[0]' refers to 'nonexisting', "
+                "The value of 'raw_id_fields[0]' refers to 'nonexistent', "
                 "which is not an attribute of 'admin_checks.Album'.",
-                obj=RawIdNonexistingAdmin,
+                obj=RawIdNonexistentAdmin,
                 id='admin.E002',
             )
         ]
diff --git a/tests/admin_scripts/tests.py b/tests/admin_scripts/tests.py
index 177d24892a..88e547a8c2 100644
--- a/tests/admin_scripts/tests.py
+++ b/tests/admin_scripts/tests.py
@@ -1132,9 +1132,7 @@ class ManageCheck(AdminScriptTestCase):
         self.remove_settings('settings.py')
 
     def test_nonexistent_app(self):
-        """ manage.py check reports an error on a non-existent app in
-        INSTALLED_APPS """
-
+        """check reports an error on a nonexistent app in INSTALLED_APPS."""
         self.write_settings(
             'settings.py',
             apps=['admin_scriptz.broken_app'],
diff --git a/tests/admin_utils/test_logentry.py b/tests/admin_utils/test_logentry.py
index c2eee96f48..b568a59336 100644
--- a/tests/admin_utils/test_logentry.py
+++ b/tests/admin_utils/test_logentry.py
@@ -150,14 +150,14 @@ class LogEntryTests(TestCase):
     def test_logentry_get_admin_url(self):
         """
         LogEntry.get_admin_url returns a URL to edit the entry's object or
-        None for non-existent (possibly deleted) models.
+        None for nonexistent (possibly deleted) models.
         """
         logentry = LogEntry.objects.get(content_type__model__iexact='article')
         expected_url = reverse('admin:admin_utils_article_change', args=(quote(self.a1.pk),))
         self.assertEqual(logentry.get_admin_url(), expected_url)
         self.assertIn('article/%d/change/' % self.a1.pk, logentry.get_admin_url())
 
-        logentry.content_type.model = "non-existent"
+        logentry.content_type.model = "nonexistent"
         self.assertIsNone(logentry.get_admin_url())
 
     def test_logentry_unicode(self):
diff --git a/tests/admin_widgets/tests.py b/tests/admin_widgets/tests.py
index b0ec18968e..aaef915ee9 100644
--- a/tests/admin_widgets/tests.py
+++ b/tests/admin_widgets/tests.py
@@ -222,7 +222,7 @@ class AdminForeignKeyRawIdWidget(TestDataMixin, TestCase):
         post_data = {
             "main_band": '%s' % pk,
         }
-        # Try posting with a non-existent pk in a raw id field: this
+        # Try posting with a nonexistent pk in a raw id field: this
         # should result in an error message, not a server exception.
         response = self.client.post(reverse('admin:admin_widgets_event_add'), post_data)
         self.assertContains(response, 'Select a valid choice. That choice is not one of the available choices.')
diff --git a/tests/auth_tests/templates/context_processors/auth_attrs_perm_in_perms.html b/tests/auth_tests/templates/context_processors/auth_attrs_perm_in_perms.html
index 3a18cd7405..04f26e624b 100644
--- a/tests/auth_tests/templates/context_processors/auth_attrs_perm_in_perms.html
+++ b/tests/auth_tests/templates/context_processors/auth_attrs_perm_in_perms.html
@@ -1,4 +1,4 @@
 {% if 'auth' in perms %}Has auth permissions{% endif %}
 {% if 'auth.add_permission' in perms %}Has auth.add_permission permissions{% endif %}
-{% if 'nonexisting' in perms %}nonexisting perm found{% endif %}
-{% if 'auth.nonexisting' in perms %}auth.nonexisting perm found{% endif %}
+{% if 'nonexistent' in perms %}nonexistent perm found{% endif %}
+{% if 'auth.nonexistent' in perms %}auth.nonexistent perm found{% endif %}
diff --git a/tests/auth_tests/templates/context_processors/auth_attrs_perms.html b/tests/auth_tests/templates/context_processors/auth_attrs_perms.html
index 6f441afc10..b1c829bd98 100644
--- a/tests/auth_tests/templates/context_processors/auth_attrs_perms.html
+++ b/tests/auth_tests/templates/context_processors/auth_attrs_perms.html
@@ -1,4 +1,4 @@
 {% if perms.auth %}Has auth permissions{% endif %}
 {% if perms.auth.add_permission %}Has auth.add_permission permissions{% endif %}
-{% if perms.nonexisting %}nonexisting perm found{% endif %}
-{% if perms.auth.nonexisting in perms %}auth.nonexisting perm found{% endif %}
+{% if perms.nonexistent %}nonexistent perm found{% endif %}
+{% if perms.auth.nonexistent in perms %}auth.nonexistent perm found{% endif %}
diff --git a/tests/auth_tests/test_context_processors.py b/tests/auth_tests/test_context_processors.py
index 5b93800386..4c4652cd1b 100644
--- a/tests/auth_tests/test_context_processors.py
+++ b/tests/auth_tests/test_context_processors.py
@@ -44,9 +44,9 @@ class PermWrapperTests(SimpleTestCase):
         perms = PermWrapper(MockUser())
         # Works for modules and full permissions.
         self.assertIn('mockapp', perms)
-        self.assertNotIn('nonexisting', perms)
+        self.assertNotIn('nonexistent', perms)
         self.assertIn('mockapp.someperm', perms)
-        self.assertNotIn('mockapp.nonexisting', perms)
+        self.assertNotIn('mockapp.nonexistent', perms)
 
     def test_permlookupdict_in(self):
         """
@@ -95,7 +95,7 @@ class AuthContextProcessorTests(TestCase):
         response = self.client.get('/auth_processor_perms/')
         self.assertContains(response, "Has auth permissions")
         self.assertContains(response, "Has auth.add_permission permissions")
-        self.assertNotContains(response, "nonexisting")
+        self.assertNotContains(response, "nonexistent")
 
     def test_perm_in_perms_attrs(self):
         u = User.objects.create_user(username='normal', password='secret')
@@ -107,7 +107,7 @@ class AuthContextProcessorTests(TestCase):
         response = self.client.get('/auth_processor_perm_in_perms/')
         self.assertContains(response, "Has auth permissions")
         self.assertContains(response, "Has auth.add_permission permissions")
-        self.assertNotContains(response, "nonexisting")
+        self.assertNotContains(response, "nonexistent")
 
     def test_message_attrs(self):
         self.client.force_login(self.superuser)
diff --git a/tests/auth_tests/test_decorators.py b/tests/auth_tests/test_decorators.py
index 55c422bdc6..befe5c4d27 100644
--- a/tests/auth_tests/test_decorators.py
+++ b/tests/auth_tests/test_decorators.py
@@ -97,7 +97,7 @@ class PermissionsRequiredDecoratorTest(TestCase):
 
     def test_permissioned_denied_redirect(self):
 
-        @permission_required(['auth_tests.add_customuser', 'auth_tests.change_customuser', 'non-existent-permission'])
+        @permission_required(['auth_tests.add_customuser', 'auth_tests.change_customuser', 'nonexistent-permission'])
         def a_view(request):
             return HttpResponse()
         request = self.factory.get('/rand')
@@ -108,7 +108,7 @@ class PermissionsRequiredDecoratorTest(TestCase):
     def test_permissioned_denied_exception_raised(self):
 
         @permission_required([
-            'auth_tests.add_customuser', 'auth_tests.change_customuser', 'non-existent-permission'
+            'auth_tests.add_customuser', 'auth_tests.change_customuser', 'nonexistent-permission'
         ], raise_exception=True)
         def a_view(request):
             return HttpResponse()
diff --git a/tests/auth_tests/test_deprecated_views.py b/tests/auth_tests/test_deprecated_views.py
index ba43140ebe..be3b990494 100644
--- a/tests/auth_tests/test_deprecated_views.py
+++ b/tests/auth_tests/test_deprecated_views.py
@@ -191,7 +191,7 @@ class PasswordResetTest(AuthViewsTestCase):
         self.assertContains(response, "The password reset link was invalid")
 
     def test_confirm_invalid_user(self):
-        # We get a 200 response for a non-existent user, not a 404
+        # We get a 200 response for a nonexistent user, not a 404
         response = self.client.get('/reset/123456/1-1/')
         self.assertContains(response, "The password reset link was invalid")
 
diff --git a/tests/auth_tests/test_mixins.py b/tests/auth_tests/test_mixins.py
index 0a0c5ccdf4..70e8f27675 100644
--- a/tests/auth_tests/test_mixins.py
+++ b/tests/auth_tests/test_mixins.py
@@ -238,7 +238,7 @@ class PermissionsRequiredMixinTests(TestCase):
     def test_permissioned_denied_redirect(self):
         class AView(PermissionRequiredMixin, EmptyResponseView):
             permission_required = [
-                'auth_tests.add_customuser', 'auth_tests.change_customuser', 'non-existent-permission',
+                'auth_tests.add_customuser', 'auth_tests.change_customuser', 'nonexistent-permission',
             ]
 
         request = self.factory.get('/rand')
@@ -249,7 +249,7 @@ class PermissionsRequiredMixinTests(TestCase):
     def test_permissioned_denied_exception_raised(self):
         class AView(PermissionRequiredMixin, EmptyResponseView):
             permission_required = [
-                'auth_tests.add_customuser', 'auth_tests.change_customuser', 'non-existent-permission',
+                'auth_tests.add_customuser', 'auth_tests.change_customuser', 'nonexistent-permission',
             ]
             raise_exception = True
 
diff --git a/tests/auth_tests/test_views.py b/tests/auth_tests/test_views.py
index cee3383f05..7436473635 100644
--- a/tests/auth_tests/test_views.py
+++ b/tests/auth_tests/test_views.py
@@ -234,7 +234,7 @@ class PasswordResetTest(AuthViewsTestCase):
         self.assertContains(response, "The password reset link was invalid")
 
     def test_confirm_invalid_user(self):
-        # A non-existent user returns a 200 response, not a 404.
+        # A nonexistent user returns a 200 response, not a 404.
         response = self.client.get('/reset/123456/1-1/')
         self.assertContains(response, "The password reset link was invalid")
 
diff --git a/tests/cache/tests.py b/tests/cache/tests.py
index 6b462f29c2..733bc1341a 100644
--- a/tests/cache/tests.py
+++ b/tests/cache/tests.py
@@ -83,7 +83,7 @@ class DummyCacheTests(SimpleTestCase):
         self.assertIsNone(cache.get("addkey1"))
 
     def test_non_existent(self):
-        "Non-existent keys aren't found in the dummy cache backend"
+        "Nonexistent keys aren't found in the dummy cache backend"
         self.assertIsNone(cache.get("does_not_exist"))
         self.assertEqual(cache.get("does_not_exist", "bang!"), "bang!")
 
@@ -280,8 +280,7 @@ class BaseCacheTests:
         self.assertEqual(caches['prefix'].get('somekey'), 'value2')
 
     def test_non_existent(self):
-        # Non-existent cache keys return as None/default
-        # get with non-existent keys
+        """Nonexistent cache keys return as None/default."""
         self.assertIsNone(cache.get("does_not_exist"))
         self.assertEqual(cache.get("does_not_exist", "bang!"), "bang!")
 
diff --git a/tests/contenttypes_tests/tests.py b/tests/contenttypes_tests/tests.py
index 794b1e34ef..14e14e0913 100644
--- a/tests/contenttypes_tests/tests.py
+++ b/tests/contenttypes_tests/tests.py
@@ -154,7 +154,7 @@ class GenericForeignKeyTests(SimpleTestCase):
         errors = TaggedItem.content_object.check()
         expected = [
             checks.Error(
-                "The GenericForeignKey content type references the non-existent field 'TaggedItem.content_type'.",
+                "The GenericForeignKey content type references the nonexistent field 'TaggedItem.content_type'.",
                 obj=TaggedItem.content_object,
                 id='contenttypes.E002',
             )
@@ -212,7 +212,7 @@ class GenericForeignKeyTests(SimpleTestCase):
         errors = TaggedItem.content_object.check()
         expected = [
             checks.Error(
-                "The GenericForeignKey object ID references the non-existent field 'object_id'.",
+                "The GenericForeignKey object ID references the nonexistent field 'object_id'.",
                 obj=TaggedItem.content_object,
                 id='contenttypes.E001',
             )
diff --git a/tests/decorators/tests.py b/tests/decorators/tests.py
index 8fedacec22..3afab467a1 100644
--- a/tests/decorators/tests.py
+++ b/tests/decorators/tests.py
@@ -384,10 +384,10 @@ class MethodDecoratorTests(SimpleTestCase):
         """
         msg = (
             "The keyword argument `name` must be the name of a method of the "
-            "decorated class: <class 'Test'>. Got 'non_existing_method' instead"
+            "decorated class: <class 'Test'>. Got 'nonexistent_method' instead"
         )
         with self.assertRaisesMessage(ValueError, msg):
-            @method_decorator(lambda: None, name="non_existing_method")
+            @method_decorator(lambda: None, name='nonexistent_method')
             class Test:
                 @classmethod
                 def __module__(cls):
diff --git a/tests/file_storage/tests.py b/tests/file_storage/tests.py
index baa6098b09..494832badd 100644
--- a/tests/file_storage/tests.py
+++ b/tests/file_storage/tests.py
@@ -44,21 +44,21 @@ class GetStorageClassTests(SimpleTestCase):
         get_storage_class raises an error if the requested import don't exist.
         """
         with self.assertRaisesMessage(ImportError, "No module named 'storage'"):
-            get_storage_class('storage.NonExistingStorage')
+            get_storage_class('storage.NonexistentStorage')
 
-    def test_get_nonexisting_storage_class(self):
+    def test_get_nonexistent_storage_class(self):
         """
         get_storage_class raises an error if the requested class don't exist.
         """
         with self.assertRaises(ImportError):
-            get_storage_class('django.core.files.storage.NonExistingStorage')
+            get_storage_class('django.core.files.storage.NonexistentStorage')
 
-    def test_get_nonexisting_storage_module(self):
+    def test_get_nonexistent_storage_module(self):
         """
         get_storage_class raises an error if the requested module don't exist.
         """
-        with self.assertRaisesMessage(ImportError, "No module named 'django.core.files.non_existing_storage'"):
-            get_storage_class('django.core.files.non_existing_storage.NonExistingStorage')
+        with self.assertRaisesMessage(ImportError, "No module named 'django.core.files.nonexistent_storage'"):
+            get_storage_class('django.core.files.nonexistent_storage.NonexistentStorage')
 
 
 class FileSystemStorageTests(unittest.TestCase):
diff --git a/tests/fixtures/tests.py b/tests/fixtures/tests.py
index a25eae18a6..fe047e9838 100644
--- a/tests/fixtures/tests.py
+++ b/tests/fixtures/tests.py
@@ -681,7 +681,7 @@ class FixtureLoadingTests(DumpDataAssertMixin, TestCase):
             management.call_command('loaddata', 'fixture1', exclude=['fixtures.FooModel'], verbosity=0)
 
 
-class NonExistentFixtureTests(TestCase):
+class NonexistentFixtureTests(TestCase):
     """
     Custom class to limit fixture dirs.
     """
diff --git a/tests/fixtures_regress/fixtures/sequence_extra.json b/tests/fixtures_regress/fixtures/sequence_extra.json
index d668ef6143..880aff8c24 100644
--- a/tests/fixtures_regress/fixtures/sequence_extra.json
+++ b/tests/fixtures_regress/fixtures/sequence_extra.json
@@ -14,7 +14,7 @@
         "pk": "1",
         "model": "fixtures_regress.animal_extra",
         "fields": {
-            "name": "Non-existent model",
+            "name": "Nonexistent model",
             "extra_name": "test for ticket #21799",
             "latin_name": "Panthera leo",
             "count": 3,
diff --git a/tests/flatpages_tests/test_csrf.py b/tests/flatpages_tests/test_csrf.py
index aa0344a930..ae2dd9755f 100644
--- a/tests/flatpages_tests/test_csrf.py
+++ b/tests/flatpages_tests/test_csrf.py
@@ -60,7 +60,10 @@ class FlatpageCSRFTests(TestCase):
         self.assertContains(response, "<p>Isn't it flat!</p>")
 
     def test_view_non_existent_flatpage(self):
-        "A non-existent flatpage raises 404 when served through a view, even when the middleware is in use"
+        """
+        A nonexistent flatpage raises 404 when served through a view, even when
+        the middleware is in use.
+        """
         response = self.client.get('/flatpage_root/no_such_flatpage/')
         self.assertEqual(response.status_code, 404)
 
@@ -79,7 +82,10 @@ class FlatpageCSRFTests(TestCase):
         self.assertContains(response, "<p>Isn't it flat!</p>")
 
     def test_fallback_non_existent_flatpage(self):
-        "A non-existent flatpage raises a 404 when served by the fallback middleware"
+        """
+        A nonexistent flatpage raises a 404 when served by the fallback
+        middleware.
+        """
         response = self.client.get('/no_such_flatpage/')
         self.assertEqual(response.status_code, 404)
 
diff --git a/tests/flatpages_tests/test_middleware.py b/tests/flatpages_tests/test_middleware.py
index b7ca196db1..22e4c2ba31 100644
--- a/tests/flatpages_tests/test_middleware.py
+++ b/tests/flatpages_tests/test_middleware.py
@@ -60,7 +60,10 @@ class FlatpageMiddlewareTests(TestDataMixin, TestCase):
         self.assertContains(response, "<p>Isn't it flat!</p>")
 
     def test_view_non_existent_flatpage(self):
-        "A non-existent flatpage raises 404 when served through a view, even when the middleware is in use"
+        """
+        A nonexistent flatpage raises 404 when served through a view, even when
+        the middleware is in use.
+        """
         response = self.client.get('/flatpage_root/no_such_flatpage/')
         self.assertEqual(response.status_code, 404)
 
@@ -79,7 +82,10 @@ class FlatpageMiddlewareTests(TestDataMixin, TestCase):
         self.assertContains(response, "<p>Isn't it flat!</p>")
 
     def test_fallback_non_existent_flatpage(self):
-        "A non-existent flatpage raises a 404 when served by the fallback middleware"
+        """
+        A nonexistent flatpage raises a 404 when served by the fallback
+        middleware.
+        """
         response = self.client.get('/no_such_flatpage/')
         self.assertEqual(response.status_code, 404)
 
@@ -131,7 +137,10 @@ class FlatpageMiddlewareAppendSlashTests(TestDataMixin, TestCase):
         self.assertRedirects(response, '/flatpage_root/flatpage/', status_code=301)
 
     def test_redirect_view_non_existent_flatpage(self):
-        "A non-existent flatpage raises 404 when served through a view and should not add a slash"
+        """
+        A nonexistent flatpage raises 404 when served through a view and
+        should not add a slash.
+        """
         response = self.client.get('/flatpage_root/no_such_flatpage')
         self.assertEqual(response.status_code, 404)
 
@@ -141,7 +150,10 @@ class FlatpageMiddlewareAppendSlashTests(TestDataMixin, TestCase):
         self.assertRedirects(response, '/flatpage/', status_code=301)
 
     def test_redirect_fallback_non_existent_flatpage(self):
-        "A non-existent flatpage raises a 404 when served by the fallback middleware and should not add a slash"
+        """
+        A nonexistent flatpage raises a 404 when served by the fallback
+        middleware and should not add a slash.
+        """
         response = self.client.get('/no_such_flatpage')
         self.assertEqual(response.status_code, 404)
 
diff --git a/tests/flatpages_tests/test_views.py b/tests/flatpages_tests/test_views.py
index 42d3e2e8cc..57b05debb4 100644
--- a/tests/flatpages_tests/test_views.py
+++ b/tests/flatpages_tests/test_views.py
@@ -60,7 +60,7 @@ class FlatpageViewTests(TestDataMixin, TestCase):
         self.assertContains(response, "<p>Isn't it flat!</p>")
 
     def test_view_non_existent_flatpage(self):
-        "A non-existent flatpage raises 404 when served through a view"
+        """A nonexistent flatpage raises 404 when served through a view."""
         response = self.client.get('/flatpage_root/no_such_flatpage/')
         self.assertEqual(response.status_code, 404)
 
@@ -79,7 +79,10 @@ class FlatpageViewTests(TestDataMixin, TestCase):
         self.assertEqual(response.status_code, 404)
 
     def test_fallback_non_existent_flatpage(self):
-        "A non-existent flatpage won't be served if the fallback middleware is disabled"
+        """
+        A nonexistent flatpage won't be served if the fallback middleware is
+        disabled.
+        """
         response = self.client.get('/no_such_flatpage/')
         self.assertEqual(response.status_code, 404)
 
@@ -122,7 +125,10 @@ class FlatpageViewAppendSlashTests(TestDataMixin, TestCase):
         self.assertRedirects(response, '/flatpage_root/flatpage/', status_code=301)
 
     def test_redirect_view_non_existent_flatpage(self):
-        "A non-existent flatpage raises 404 when served through a view and should not add a slash"
+        """
+        A nonexistent flatpage raises 404 when served through a view and
+        should not add a slash.
+        """
         response = self.client.get('/flatpage_root/no_such_flatpage')
         self.assertEqual(response.status_code, 404)
 
@@ -132,7 +138,10 @@ class FlatpageViewAppendSlashTests(TestDataMixin, TestCase):
         self.assertEqual(response.status_code, 404)
 
     def test_redirect_fallback_non_existent_flatpage(self):
-        "A non-existent flatpage won't be served if the fallback middleware is disabled and should not add a slash"
+        """
+        A nonexistent flatpage won't be served if the fallback middleware is
+        disabled and should not add a slash.
+        """
         response = self.client.get('/no_such_flatpage')
         self.assertEqual(response.status_code, 404)
 
diff --git a/tests/i18n/patterns/tests.py b/tests/i18n/patterns/tests.py
index 35b879d11a..7637362254 100644
--- a/tests/i18n/patterns/tests.py
+++ b/tests/i18n/patterns/tests.py
@@ -150,7 +150,7 @@ class URLTranslationTests(URLTestCaseBase):
 
     def test_translate_url_utility(self):
         with translation.override('en'):
-            self.assertEqual(translate_url('/en/non-existent/', 'nl'), '/en/non-existent/')
+            self.assertEqual(translate_url('/en/nonexistent/', 'nl'), '/en/nonexistent/')
             self.assertEqual(translate_url('/en/users/', 'nl'), '/nl/gebruikers/')
             # Namespaced URL
             self.assertEqual(translate_url('/en/account/register/', 'nl'), '/nl/profiel/registeren/')
diff --git a/tests/invalid_models_tests/test_models.py b/tests/invalid_models_tests/test_models.py
index d35f9aa063..77d180d791 100644
--- a/tests/invalid_models_tests/test_models.py
+++ b/tests/invalid_models_tests/test_models.py
@@ -88,7 +88,7 @@ class IndexTogetherTests(SimpleTestCase):
         errors = Model.check()
         expected = [
             Error(
-                "'index_together' refers to the non-existent field 'missing_field'.",
+                "'index_together' refers to the nonexistent field 'missing_field'.",
                 obj=Model,
                 id='models.E012',
             ),
@@ -214,7 +214,7 @@ class UniqueTogetherTests(SimpleTestCase):
         errors = Model.check()
         expected = [
             Error(
-                "'unique_together' refers to the non-existent field 'missing_field'.",
+                "'unique_together' refers to the nonexistent field 'missing_field'.",
                 obj=Model,
                 id='models.E012',
             ),
@@ -631,7 +631,7 @@ class OtherModelTests(SimpleTestCase):
         errors = Model.check()
         expected = [
             Error(
-                "'ordering' refers to the non-existent field 'relation'.",
+                "'ordering' refers to the nonexistent field 'relation'.",
                 obj=Model,
                 id='models.E015',
             ),
@@ -646,7 +646,7 @@ class OtherModelTests(SimpleTestCase):
         errors = Model.check()
         expected = [
             Error(
-                "'ordering' refers to the non-existent field 'missing_field'.",
+                "'ordering' refers to the nonexistent field 'missing_field'.",
                 obj=Model,
                 id='models.E015',
             )
@@ -665,7 +665,7 @@ class OtherModelTests(SimpleTestCase):
         errors = Model.check()
         expected = [
             Error(
-                "'ordering' refers to the non-existent field 'missing_fk_field_id'.",
+                "'ordering' refers to the nonexistent field 'missing_fk_field_id'.",
                 obj=Model,
                 id='models.E015',
             )
diff --git a/tests/lookup/tests.py b/tests/lookup/tests.py
index 1da7084e48..f826a480a1 100644
--- a/tests/lookup/tests.py
+++ b/tests/lookup/tests.py
@@ -252,7 +252,7 @@ class LookupTests(TestCase):
             ],
         )
         # However, an exception FieldDoesNotExist will be thrown if you specify
-        # a non-existent field name in values() (a field that is neither in the
+        # a nonexistent field name in values() (a field that is neither in the
         # model nor in extra(select)).
         with self.assertRaises(FieldError):
             Article.objects.extra(select={'id_plus_one': 'id + 1'}).values('id', 'id_plus_two')
diff --git a/tests/migrations/test_commands.py b/tests/migrations/test_commands.py
index af83eb0a6a..699a3e994a 100644
--- a/tests/migrations/test_commands.py
+++ b/tests/migrations/test_commands.py
@@ -772,9 +772,7 @@ class MakeMigrationsTests(MigrationTestBase):
         self.assertIn("No conflicts detected to merge.", out.getvalue())
 
     def test_makemigrations_no_app_sys_exit(self):
-        """
-        makemigrations exits if a non-existent app is specified.
-        """
+        """makemigrations exits if a nonexistent app is specified."""
         err = io.StringIO()
         with self.assertRaises(SystemExit):
             call_command("makemigrations", "this_app_does_not_exist", stderr=err)
diff --git a/tests/migrations/test_loader.py b/tests/migrations/test_loader.py
index b06ff8f89c..61b1643506 100644
--- a/tests/migrations/test_loader.py
+++ b/tests/migrations/test_loader.py
@@ -351,7 +351,7 @@ class LoaderTests(TestCase):
         loader.build_graph()
         self.assertEqual(num_nodes(), 3)
 
-        # However, starting at 3 or 4 we'd need to use non-existing migrations
+        # However, starting at 3 or 4, nonexistent migrations would be needed.
         msg = ("Migration migrations.6_auto depends on nonexistent node ('migrations', '5_auto'). "
                "Django tried to replace migration migrations.5_auto with any of "
                "[migrations.3_squashed_5] but wasn't able to because some of the replaced "
diff --git a/tests/queries/tests.py b/tests/queries/tests.py
index 8fe2af644f..d6e726d4d3 100644
--- a/tests/queries/tests.py
+++ b/tests/queries/tests.py
@@ -2827,13 +2827,13 @@ class EmptyStringsAsNullTest(TestCase):
 
     def test_direct_exclude(self):
         self.assertQuerysetEqual(
-            NamedCategory.objects.exclude(name__in=['nonexisting']),
+            NamedCategory.objects.exclude(name__in=['nonexistent']),
             [self.nc.pk], attrgetter('pk')
         )
 
     def test_joined_exclude(self):
         self.assertQuerysetEqual(
-            DumbCategory.objects.exclude(namedcategory__name__in=['nonexisting']),
+            DumbCategory.objects.exclude(namedcategory__name__in=['nonexistent']),
             [self.nc.pk], attrgetter('pk')
         )
 
diff --git a/tests/template_backends/test_dummy.py b/tests/template_backends/test_dummy.py
index 5e1639cd80..92861c24da 100644
--- a/tests/template_backends/test_dummy.py
+++ b/tests/template_backends/test_dummy.py
@@ -37,9 +37,9 @@ class TemplateStringsTests(SimpleTestCase):
         content = template.render({'name': 'world'})
         self.assertEqual(content, "Hello world!\n")
 
-    def test_get_template_non_existing(self):
+    def test_get_template_nonexistent(self):
         with self.assertRaises(TemplateDoesNotExist) as e:
-            self.engine.get_template('template_backends/non_existing.html')
+            self.engine.get_template('template_backends/nonexistent.html')
         self.assertEqual(e.exception.backend, self.engine)
 
     def test_get_template_syntax_error(self):
diff --git a/tests/template_tests/syntax_tests/test_if.py b/tests/template_tests/syntax_tests/test_if.py
index 40593c7694..5ea57bf489 100644
--- a/tests/template_tests/syntax_tests/test_if.py
+++ b/tests/template_tests/syntax_tests/test_if.py
@@ -533,9 +533,7 @@ class IfTagTests(SimpleTestCase):
 
     @setup({'if-tag-badarg01': '{% if x|default_if_none:y %}yes{% endif %}'})
     def test_if_tag_badarg01(self):
-        """
-        Non-existent args
-        """
+        """Nonexistent args"""
         output = self.engine.render_to_string('if-tag-badarg01')
         self.assertEqual(output, '')
 
diff --git a/tests/template_tests/templates/included_content.html b/tests/template_tests/templates/included_content.html
index bfc87c0425..cc033bd3b9 100644
--- a/tests/template_tests/templates/included_content.html
+++ b/tests/template_tests/templates/included_content.html
@@ -7,5 +7,5 @@
 
 {% block error_here %}
   error here
-  {% url "non_existing_url" %}
+  {% url "nonexistent_url" %}
 {% endblock %}
diff --git a/tests/test_client_regress/tests.py b/tests/test_client_regress/tests.py
index e5f9eb97b9..e4fd2bb8fe 100644
--- a/tests/test_client_regress/tests.py
+++ b/tests/test_client_regress/tests.py
@@ -391,7 +391,7 @@ class AssertRedirectsTests(SimpleTestCase):
         self.assertEqual(response.redirect_chain[2], ('/no_template_view/', 302))
 
     def test_redirect_chain_to_non_existent(self):
-        "You can follow a chain to a non-existent view"
+        "You can follow a chain to a nonexistent view."
         response = self.client.get('/redirect_to_non_existent_view2/', {}, follow=True)
         self.assertRedirects(response, '/non_existent_view/', status_code=302, target_status_code=404)
 
diff --git a/tests/test_runner/tests.py b/tests/test_runner/tests.py
index 2de8122135..b6d3751489 100644
--- a/tests/test_runner/tests.py
+++ b/tests/test_runner/tests.py
@@ -147,7 +147,7 @@ class ManageCommandTests(unittest.TestCase):
 
     def test_bad_test_runner(self):
         with self.assertRaises(AttributeError):
-            call_command('test', 'sites', testrunner='test_runner.NonExistentRunner')
+            call_command('test', 'sites', testrunner='test_runner.NonexistentRunner')
 
 
 class CustomTestRunnerOptionsTests(AdminScriptTestCase):
diff --git a/tests/urlpatterns_reverse/tests.py b/tests/urlpatterns_reverse/tests.py
index 8d4cedc2e7..c4c1c9775d 100644
--- a/tests/urlpatterns_reverse/tests.py
+++ b/tests/urlpatterns_reverse/tests.py
@@ -337,11 +337,11 @@ class URLPatternReverse(SimpleTestCase):
 
     def test_view_not_found_message(self):
         msg = (
-            "Reverse for 'non-existent-view' not found. 'non-existent-view' "
+            "Reverse for 'nonexistent-view' not found. 'nonexistent-view' "
             "is not a valid view function or pattern name."
         )
         with self.assertRaisesMessage(NoReverseMatch, msg):
-            reverse('non-existent-view')
+            reverse('nonexistent-view')
 
     def test_no_args_message(self):
         msg = "Reverse for 'places' with no arguments not found. 1 pattern(s) tried:"
@@ -410,8 +410,8 @@ class ResolverTests(SimpleTestCase):
         """
         urls = 'urlpatterns_reverse.named_urls'
         # this list matches the expected URL types and names returned when
-        # you try to resolve a non-existent URL in the first level of included
-        # URLs in named_urls.py (e.g., '/included/non-existent-url')
+        # you try to resolve a nonexistent URL in the first level of included
+        # URLs in named_urls.py (e.g., '/included/nonexistent-url')
         url_types_names = [
             [{'type': RegexURLPattern, 'name': 'named-url1'}],
             [{'type': RegexURLPattern, 'name': 'named-url2'}],
@@ -422,7 +422,7 @@ class ResolverTests(SimpleTestCase):
             [{'type': RegexURLResolver}, {'type': RegexURLResolver}],
         ]
         with self.assertRaisesMessage(Resolver404, 'tried') as cm:
-            resolve('/included/non-existent-url', urlconf=urls)
+            resolve('/included/nonexistent-url', urlconf=urls)
         e = cm.exception
         # make sure we at least matched the root ('/') url resolver:
         self.assertIn('tried', e.args[0])
@@ -594,7 +594,7 @@ class NamespaceTests(SimpleTestCase):
             reverse('inner-nothing', kwargs={'arg1': 42, 'arg2': 37})
 
     def test_non_existent_namespace(self):
-        "Non-existent namespaces raise errors"
+        "Nonexistent namespaces raise errors"
         with self.assertRaises(NoReverseMatch):
             reverse('blahblah:urlobject-view')
         with self.assertRaises(NoReverseMatch):
@@ -804,20 +804,20 @@ class NamespaceTests(SimpleTestCase):
         "current_app should either match the whole path or shouldn't be used"
         self.assertEqual(
             '/ns-included1/test4/inner/',
-            reverse('inc-ns1:testapp:urlobject-view', current_app='non-existent:test-ns3')
+            reverse('inc-ns1:testapp:urlobject-view', current_app='nonexistent:test-ns3')
         )
         self.assertEqual(
             '/ns-included1/test4/inner/37/42/',
-            reverse('inc-ns1:testapp:urlobject-view', args=[37, 42], current_app='non-existent:test-ns3')
+            reverse('inc-ns1:testapp:urlobject-view', args=[37, 42], current_app='nonexistent:test-ns3')
         )
         self.assertEqual(
             '/ns-included1/test4/inner/42/37/',
             reverse('inc-ns1:testapp:urlobject-view', kwargs={'arg1': 42, 'arg2': 37},
-                    current_app='non-existent:test-ns3')
+                    current_app='nonexistent:test-ns3')
         )
         self.assertEqual(
             '/ns-included1/test4/inner/+%5C$*/',
-            reverse('inc-ns1:testapp:urlobject-special-view', current_app='non-existent:test-ns3')
+            reverse('inc-ns1:testapp:urlobject-special-view', current_app='nonexistent:test-ns3')
         )
 
 
diff --git a/tests/view_tests/tests/test_defaults.py b/tests/view_tests/tests/test_defaults.py
index 4b002f3632..62c3fc7619 100644
--- a/tests/view_tests/tests/test_defaults.py
+++ b/tests/view_tests/tests/test_defaults.py
@@ -15,8 +15,10 @@ from ..models import Article, Author, UrlArticle
 @override_settings(ROOT_URLCONF='view_tests.urls')
 class DefaultsTests(TestCase):
     """Test django views in django/views/defaults.py"""
-    non_existing_urls = ['/non_existing_url/',  # this is in urls.py
-                         '/other_non_existing_url/']  # this NOT in urls.py
+    nonexistent_urls = [
+        '/nonexistent_url/',  # this is in urls.py
+        '/other_nonexistent_url/',  # this NOT in urls.py
+    ]
 
     @classmethod
     def setUpTestData(cls):
@@ -41,7 +43,7 @@ class DefaultsTests(TestCase):
 
     def test_page_not_found(self):
         "A 404 status is returned by the page_not_found view"
-        for url in self.non_existing_urls:
+        for url in self.nonexistent_urls:
             response = self.client.get(url)
             self.assertEqual(response.status_code, 404)
 
@@ -60,7 +62,7 @@ class DefaultsTests(TestCase):
         The 404 page should have the csrf_token available in the context
         """
         # See ticket #14565
-        for url in self.non_existing_urls:
+        for url in self.nonexistent_urls:
             response = self.client.get(url)
             self.assertNotEqual(response.content, 'NOTPROVIDED')
             self.assertNotEqual(response.content, '')
@@ -113,7 +115,7 @@ class DefaultsTests(TestCase):
         response = self.client.get('/raises403/')
         self.assertEqual(response['Content-Type'], 'text/html')
 
-        response = self.client.get('/non_existing_url/')
+        response = self.client.get('/nonexistent_url/')
         self.assertEqual(response['Content-Type'], 'text/html')
 
         response = self.client.get('/server_error/')
diff --git a/tests/view_tests/tests/test_static.py b/tests/view_tests/tests/test_static.py
index 01b4c2de7d..f7e5604d06 100644
--- a/tests/view_tests/tests/test_static.py
+++ b/tests/view_tests/tests/test_static.py
@@ -104,7 +104,7 @@ class StaticTests(SimpleTestCase):
         self.assertEqual(len(response_content), int(response['Content-Length']))
 
     def test_404(self):
-        response = self.client.get('/%s/non_existing_resource' % self.prefix)
+        response = self.client.get('/%s/nonexistent_resource' % self.prefix)
         self.assertEqual(404, response.status_code)
 
     def test_index(self):
diff --git a/tests/view_tests/urls.py b/tests/view_tests/urls.py
index c046336b7f..26130f37bb 100644
--- a/tests/view_tests/urls.py
+++ b/tests/view_tests/urls.py
@@ -56,7 +56,7 @@ urlpatterns = [
     url(r'^$', views.index_page),
 
     # Default views
-    url(r'^non_existing_url/', partial(defaults.page_not_found, exception=None)),
+    url(r'^nonexistent_url/', partial(defaults.page_not_found, exception=None)),
     url(r'^server_error/', defaults.server_error),
 
     # a view that raises an exception for the debug view