diff --git a/MANIFEST.in b/MANIFEST.in
index be49755e0fe..03464ceff17 100644
--- a/MANIFEST.in
+++ b/MANIFEST.in
@@ -21,8 +21,6 @@ recursive-include django/contrib/admindocs/templates *
 recursive-include django/contrib/auth/fixtures *
 recursive-include django/contrib/auth/templates *
 recursive-include django/contrib/auth/tests/templates *
-recursive-include django/contrib/flatpages/fixtures *
-recursive-include django/contrib/flatpages/tests/templates *
 recursive-include django/contrib/gis/gdal/tests/data *
 recursive-include django/contrib/gis/static *
 recursive-include django/contrib/gis/templates *
diff --git a/django/contrib/flatpages/tests/templates/404.html b/django/contrib/flatpages/tests/templates/404.html
deleted file mode 100644
index cbfff0cf2f0..00000000000
--- a/django/contrib/flatpages/tests/templates/404.html
+++ /dev/null
@@ -1 +0,0 @@
-<h1>Oh Noes!</h1>
diff --git a/django/contrib/flatpages/tests/__init__.py b/tests/flatpages_tests/__init__.py
similarity index 100%
rename from django/contrib/flatpages/tests/__init__.py
rename to tests/flatpages_tests/__init__.py
diff --git a/django/contrib/flatpages/fixtures/example_site.json b/tests/flatpages_tests/fixtures/example_site.json
similarity index 100%
rename from django/contrib/flatpages/fixtures/example_site.json
rename to tests/flatpages_tests/fixtures/example_site.json
diff --git a/django/contrib/flatpages/fixtures/sample_flatpages.json b/tests/flatpages_tests/fixtures/sample_flatpages.json
similarity index 100%
rename from django/contrib/flatpages/fixtures/sample_flatpages.json
rename to tests/flatpages_tests/fixtures/sample_flatpages.json
diff --git a/django/contrib/flatpages/tests/settings.py b/tests/flatpages_tests/settings.py
similarity index 100%
rename from django/contrib/flatpages/tests/settings.py
rename to tests/flatpages_tests/settings.py
diff --git a/django/contrib/flatpages/tests/templates/flatpages/default.html b/tests/flatpages_tests/templates/flatpages/default.html
similarity index 100%
rename from django/contrib/flatpages/tests/templates/flatpages/default.html
rename to tests/flatpages_tests/templates/flatpages/default.html
diff --git a/django/contrib/flatpages/tests/templates/registration/login.html b/tests/flatpages_tests/templates/registration/login.html
similarity index 100%
rename from django/contrib/flatpages/tests/templates/registration/login.html
rename to tests/flatpages_tests/templates/registration/login.html
diff --git a/django/contrib/flatpages/tests/test_csrf.py b/tests/flatpages_tests/test_csrf.py
similarity index 94%
rename from django/contrib/flatpages/tests/test_csrf.py
rename to tests/flatpages_tests/test_csrf.py
index f8616b39139..a3dd8d2cdd9 100644
--- a/django/contrib/flatpages/tests/test_csrf.py
+++ b/tests/flatpages_tests/test_csrf.py
@@ -1,10 +1,10 @@
 from django.contrib.auth.models import User
-from django.contrib.auth.tests.utils import skipIfCustomUser
-from django.test import Client, TestCase, override_settings
+from django.test import Client, TestCase, modify_settings, override_settings
 
 from .settings import FLATPAGES_TEMPLATES
 
 
+@modify_settings(INSTALLED_APPS={'append': 'django.contrib.flatpages'})
 @override_settings(
     LOGIN_URL='/accounts/login/',
     MIDDLEWARE_CLASSES=[
@@ -15,7 +15,7 @@ from .settings import FLATPAGES_TEMPLATES
         'django.contrib.messages.middleware.MessageMiddleware',
         'django.contrib.flatpages.middleware.FlatpageFallbackMiddleware',
     ],
-    ROOT_URLCONF='django.contrib.flatpages.tests.urls',
+    ROOT_URLCONF='flatpages_tests.urls',
     CSRF_FAILURE_VIEW='django.views.csrf.csrf_failure',
     TEMPLATES=FLATPAGES_TEMPLATES,
     SITE_ID=1,
@@ -37,7 +37,6 @@ class FlatpageCSRFTests(TestCase):
         response = self.client.get('/flatpage_root/no_such_flatpage/')
         self.assertEqual(response.status_code, 404)
 
-    @skipIfCustomUser
     def test_view_authenticated_flatpage(self):
         "A flatpage served through a view can require authentication"
         response = self.client.get('/flatpage_root/sekrit/')
diff --git a/django/contrib/flatpages/tests/test_forms.py b/tests/flatpages_tests/test_forms.py
similarity index 92%
rename from django/contrib/flatpages/tests/test_forms.py
rename to tests/flatpages_tests/test_forms.py
index 09f500c6ae9..8f05d8562b2 100644
--- a/django/contrib/flatpages/tests/test_forms.py
+++ b/tests/flatpages_tests/test_forms.py
@@ -3,15 +3,20 @@ from __future__ import unicode_literals
 from django.conf import settings
 from django.contrib.flatpages.forms import FlatpageForm
 from django.contrib.flatpages.models import FlatPage
-from django.test import TestCase, override_settings
+from django.contrib.sites.models import Site
+from django.test import TestCase, modify_settings, override_settings
 from django.utils import translation
 
 
+@modify_settings(INSTALLED_APPS={'append': ['django.contrib.flatpages', ]})
 @override_settings(SITE_ID=1)
 class FlatpageAdminFormTests(TestCase):
     fixtures = ['example_site']
 
     def setUp(self):
+        # Site fields cache needs to be cleared after flatpages is added to
+        # INSTALLED_APPS
+        Site._meta._expire_cache()
         self.form_data = {
             'title': "A test page",
             'content': "This is a test",
diff --git a/django/contrib/flatpages/tests/test_middleware.py b/tests/flatpages_tests/test_middleware.py
similarity index 95%
rename from django/contrib/flatpages/tests/test_middleware.py
rename to tests/flatpages_tests/test_middleware.py
index f132aa07ace..26267036b21 100644
--- a/django/contrib/flatpages/tests/test_middleware.py
+++ b/tests/flatpages_tests/test_middleware.py
@@ -1,12 +1,12 @@
 from django.conf import settings
 from django.contrib.auth.models import User
-from django.contrib.auth.tests.utils import skipIfCustomUser
 from django.contrib.flatpages.models import FlatPage
-from django.test import TestCase, override_settings
+from django.test import TestCase, modify_settings, override_settings
 
 from .settings import FLATPAGES_TEMPLATES
 
 
+@modify_settings(INSTALLED_APPS={'append': 'django.contrib.flatpages'})
 @override_settings(
     LOGIN_URL='/accounts/login/',
     MIDDLEWARE_CLASSES=[
@@ -17,7 +17,7 @@ from .settings import FLATPAGES_TEMPLATES
         'django.contrib.messages.middleware.MessageMiddleware',
         'django.contrib.flatpages.middleware.FlatpageFallbackMiddleware',
     ],
-    ROOT_URLCONF='django.contrib.flatpages.tests.urls',
+    ROOT_URLCONF='flatpages_tests.urls',
     TEMPLATES=FLATPAGES_TEMPLATES,
     SITE_ID=1,
 )
@@ -35,7 +35,6 @@ class FlatpageMiddlewareTests(TestCase):
         response = self.client.get('/flatpage_root/no_such_flatpage/')
         self.assertEqual(response.status_code, 404)
 
-    @skipIfCustomUser
     def test_view_authenticated_flatpage(self):
         "A flatpage served through a view can require authentication"
         response = self.client.get('/flatpage_root/sekrit/')
@@ -57,7 +56,6 @@ class FlatpageMiddlewareTests(TestCase):
         response = self.client.get('/no_such_flatpage/')
         self.assertEqual(response.status_code, 404)
 
-    @skipIfCustomUser
     def test_fallback_authenticated_flatpage(self):
         "A flatpage served by the middleware can require authentication"
         response = self.client.get('/sekrit/')
@@ -84,6 +82,7 @@ class FlatpageMiddlewareTests(TestCase):
         self.assertContains(response, "<p>Isn't it special!</p>")
 
 
+@modify_settings(INSTALLED_APPS={'append': 'django.contrib.flatpages'})
 @override_settings(
     APPEND_SLASH=True,
     LOGIN_URL='/accounts/login/',
@@ -95,7 +94,7 @@ class FlatpageMiddlewareTests(TestCase):
         'django.contrib.messages.middleware.MessageMiddleware',
         'django.contrib.flatpages.middleware.FlatpageFallbackMiddleware',
     ],
-    ROOT_URLCONF='django.contrib.flatpages.tests.urls',
+    ROOT_URLCONF='flatpages_tests.urls',
     TEMPLATES=FLATPAGES_TEMPLATES,
     SITE_ID=1,
 )
diff --git a/django/contrib/flatpages/tests/test_models.py b/tests/flatpages_tests/test_models.py
similarity index 100%
rename from django/contrib/flatpages/tests/test_models.py
rename to tests/flatpages_tests/test_models.py
diff --git a/django/contrib/flatpages/tests/test_sitemaps.py b/tests/flatpages_tests/test_sitemaps.py
similarity index 87%
rename from django/contrib/flatpages/tests/test_sitemaps.py
rename to tests/flatpages_tests/test_sitemaps.py
index dcfbef4e29e..5be4fe518a2 100644
--- a/django/contrib/flatpages/tests/test_sitemaps.py
+++ b/tests/flatpages_tests/test_sitemaps.py
@@ -7,10 +7,14 @@ from django.test.utils import modify_settings, override_settings
 
 
 @override_settings(
-    ROOT_URLCONF='django.contrib.flatpages.tests.urls',
+    ROOT_URLCONF='flatpages_tests.urls',
     SITE_ID=1,
 )
-@modify_settings(INSTALLED_APPS={'append': ['django.contrib.sitemaps']},)
+@modify_settings(
+    INSTALLED_APPS={
+        'append': ['django.contrib.sitemaps', 'django.contrib.flatpages'],
+    },
+)
 class FlatpagesSitemapTests(TestCase):
 
     @classmethod
diff --git a/django/contrib/flatpages/tests/test_templatetags.py b/tests/flatpages_tests/test_templatetags.py
similarity index 96%
rename from django/contrib/flatpages/tests/test_templatetags.py
rename to tests/flatpages_tests/test_templatetags.py
index 209332b79c4..de88890e11b 100644
--- a/django/contrib/flatpages/tests/test_templatetags.py
+++ b/tests/flatpages_tests/test_templatetags.py
@@ -1,11 +1,11 @@
 from django.contrib.auth.models import AnonymousUser, User
-from django.contrib.auth.tests.utils import skipIfCustomUser
 from django.template import Context, Template, TemplateSyntaxError
-from django.test import TestCase, override_settings
+from django.test import TestCase, modify_settings, override_settings
 
 from .settings import FLATPAGES_TEMPLATES
 
 
+@modify_settings(INSTALLED_APPS={'append': 'django.contrib.flatpages'})
 @override_settings(
     MIDDLEWARE_CLASSES=[
         'django.middleware.common.CommonMiddleware',
@@ -15,7 +15,7 @@ from .settings import FLATPAGES_TEMPLATES
         'django.contrib.messages.middleware.MessageMiddleware',
         'django.contrib.flatpages.middleware.FlatpageFallbackMiddleware',
     ],
-    ROOT_URLCONF='django.contrib.flatpages.tests.urls',
+    ROOT_URLCONF='flatpages_tests.urls',
     TEMPLATES=FLATPAGES_TEMPLATES,
     SITE_ID=1,
 )
@@ -46,7 +46,6 @@ class FlatpageTemplateTagTests(TestCase):
         }))
         self.assertEqual(out, "A Flatpage,A Nested Flatpage,")
 
-    @skipIfCustomUser
     def test_get_flatpages_tag_for_user(self):
         "The flatpage template tag retrives all flatpages for an authenticated user"
         me = User.objects.create_user('testuser', 'test@example.com', 's3krit')
@@ -85,7 +84,6 @@ class FlatpageTemplateTagTests(TestCase):
         }))
         self.assertEqual(out, "A Nested Flatpage,")
 
-    @skipIfCustomUser
     def test_get_flatpages_with_prefix_for_user(self):
         "The flatpage template tag retrieve prefixed flatpages for an authenticated user"
         me = User.objects.create_user('testuser', 'test@example.com', 's3krit')
diff --git a/django/contrib/flatpages/tests/test_views.py b/tests/flatpages_tests/test_views.py
similarity index 94%
rename from django/contrib/flatpages/tests/test_views.py
rename to tests/flatpages_tests/test_views.py
index 26c071c3118..7582a7284a5 100644
--- a/django/contrib/flatpages/tests/test_views.py
+++ b/tests/flatpages_tests/test_views.py
@@ -1,12 +1,12 @@
 from django.conf import settings
 from django.contrib.auth.models import User
-from django.contrib.auth.tests.utils import skipIfCustomUser
 from django.contrib.flatpages.models import FlatPage
-from django.test import TestCase, override_settings
+from django.test import TestCase, modify_settings, override_settings
 
 from .settings import FLATPAGES_TEMPLATES
 
 
+@modify_settings(INSTALLED_APPS={'append': 'django.contrib.flatpages'})
 @override_settings(
     LOGIN_URL='/accounts/login/',
     MIDDLEWARE_CLASSES=[
@@ -17,7 +17,7 @@ from .settings import FLATPAGES_TEMPLATES
         'django.contrib.messages.middleware.MessageMiddleware',
         # no 'django.contrib.flatpages.middleware.FlatpageFallbackMiddleware'
     ],
-    ROOT_URLCONF='django.contrib.flatpages.tests.urls',
+    ROOT_URLCONF='flatpages_tests.urls',
     TEMPLATES=FLATPAGES_TEMPLATES,
     SITE_ID=1,
 )
@@ -35,7 +35,6 @@ class FlatpageViewTests(TestCase):
         response = self.client.get('/flatpage_root/no_such_flatpage/')
         self.assertEqual(response.status_code, 404)
 
-    @skipIfCustomUser
     def test_view_authenticated_flatpage(self):
         "A flatpage served through a view can require authentication"
         response = self.client.get('/flatpage_root/sekrit/')
@@ -72,6 +71,7 @@ class FlatpageViewTests(TestCase):
         self.assertContains(response, "<p>Isn't it special!</p>")
 
 
+@modify_settings(INSTALLED_APPS={'append': 'django.contrib.flatpages'})
 @override_settings(
     APPEND_SLASH=True,
     LOGIN_URL='/accounts/login/',
@@ -83,7 +83,7 @@ class FlatpageViewTests(TestCase):
         'django.contrib.messages.middleware.MessageMiddleware',
         # no 'django.contrib.flatpages.middleware.FlatpageFallbackMiddleware'
     ],
-    ROOT_URLCONF='django.contrib.flatpages.tests.urls',
+    ROOT_URLCONF='flatpages_tests.urls',
     TEMPLATES=FLATPAGES_TEMPLATES,
     SITE_ID=1,
 )
diff --git a/django/contrib/flatpages/tests/urls.py b/tests/flatpages_tests/urls.py
similarity index 100%
rename from django/contrib/flatpages/tests/urls.py
rename to tests/flatpages_tests/urls.py
diff --git a/tests/runtests.py b/tests/runtests.py
index fe3049dfa4a..1bb3c5699e7 100755
--- a/tests/runtests.py
+++ b/tests/runtests.py
@@ -60,6 +60,14 @@ ALWAYS_MIDDLEWARE_CLASSES = [
     'django.contrib.messages.middleware.MessageMiddleware',
 ]
 
+# Need to add the associated contrib app to INSTALLED_APPS in some cases to
+# avoid "RuntimeError: Model class X doesn't declare an explicit app_label
+# and either isn't in an application in INSTALLED_APPS or else was imported
+# before its application was loaded."
+CONTRIB_TESTS_TO_APPS = {
+    'flatpages_tests': 'django.contrib.flatpages',
+}
+
 
 def get_test_modules():
     modules = []
@@ -140,6 +148,7 @@ def setup(verbosity, test_labels):
         # us skip creating migrations for the test models.
         'auth': 'django.contrib.auth.tests.migrations',
         'contenttypes': 'django.contrib.contenttypes.tests.migrations',
+        'flatpages_tests': 'django.contrib.flatpages.migrations',
     }
 
     if verbosity > 0:
@@ -189,6 +198,9 @@ def setup(verbosity, test_labels):
                 module_label == label or module_label.startswith(label + '.')
                 for label in test_labels_set)
 
+        if module_name in CONTRIB_TESTS_TO_APPS and module_found_in_labels:
+            settings.INSTALLED_APPS.append(CONTRIB_TESTS_TO_APPS[module_name])
+
         if module_found_in_labels and module_label not in installed_app_names:
             if verbosity >= 2:
                 print("Importing application %s" % module_name)