Formalize URLPatternsTestCase (#5703)

* Add formalized URLPatternsTestCase

* Update versioning tests w/ new URLPatternsTestCase

* Cleanup router tests urlpatterns

* Add docs for URLPatternsTestCase

docs/api-guide/testing.md

@@ -292,7 +292,7 @@ similar way as with `RequestsClient`.
 
 ---
 
-# Test cases
+# API Test cases
 
 REST framework includes the following test case classes, that mirror the existing Django test case classes, but use `APIClient` instead of Django's default `Client`.
 
@@ -324,6 +324,32 @@ You can use any of REST framework's test case classes as you would for the regul
 
 ---
 
+# URLPatternsTestCase
+
+REST framework also provides a test case class for isolating `urlpatterns` on a per-class basis. Note that this inherits from Django's `SimpleTestCase`, and will most likely need to be mixed with another test case class.
+
+## Example
+
+    from django.urls import include, path, reverse
+    from rest_framework.test import APITestCase, URLPatternsTestCase
+
+
+    class AccountTests(APITestCase, URLPatternsTestCase):
+        urlpatterns = [
+            path('api/', include('api.urls')),
+        ]
+
+        def test_create_account(self):
+            """
+            Ensure we can create a new account object.
+            """
+            url = reverse('account-list')
+            response = self.client.get(url, format='json')
+            self.assertEqual(response.status_code, status.HTTP_200_OK)
+            self.assertEqual(len(response.data), 1)
+
+---
+
 # Testing responses
 
 ## Checking the response data

rest_framework/test.py

@@ -5,11 +5,12 @@
 from __future__ import unicode_literals
 
 import io
+from importlib import import_module
 
 from django.conf import settings
 from django.core.exceptions import ImproperlyConfigured
 from django.core.handlers.wsgi import WSGIHandler
-from django.test import testcases
+from django.test import override_settings, testcases
 from django.test.client import Client as DjangoClient
 from django.test.client import RequestFactory as DjangoRequestFactory
 from django.test.client import ClientHandler
@@ -358,3 +359,44 @@ class APISimpleTestCase(testcases.SimpleTestCase):
 
 class APILiveServerTestCase(testcases.LiveServerTestCase):
     client_class = APIClient
+
+
+class URLPatternsTestCase(testcases.SimpleTestCase):
+    """
+    Isolate URL patterns on a per-TestCase basis. For example,
+
+    class ATestCase(URLPatternsTestCase):
+        urlpatterns = [...]
+
+        def test_something(self):
+            ...
+
+    class AnotherTestCase(URLPatternsTestCase):
+        urlpatterns = [...]
+
+        def test_something_else(self):
+            ...
+    """
+    @classmethod
+    def setUpClass(cls):
+        # Get the module of the TestCase subclass
+        cls._module = import_module(cls.__module__)
+        cls._override = override_settings(ROOT_URLCONF=cls.__module__)
+
+        if hasattr(cls._module, 'urlpatterns'):
+            cls._module_urlpatterns = cls._module.urlpatterns
+
+        cls._module.urlpatterns = cls.urlpatterns
+
+        cls._override.enable()
+        super(URLPatternsTestCase, cls).setUpClass()
+
+    @classmethod
+    def tearDownClass(cls):
+        super(URLPatternsTestCase, cls).tearDownClass()
+        cls._override.disable()
+
+        if hasattr(cls, '_module_urlpatterns'):
+            cls._module.urlpatterns = cls._module_urlpatterns
+        else:
+            del cls._module.urlpatterns

tests/test_routers.py

@@ -14,7 +14,7 @@ from rest_framework.compat import get_regex_pattern
 from rest_framework.decorators import detail_route, list_route
 from rest_framework.response import Response
 from rest_framework.routers import DefaultRouter, SimpleRouter
-from rest_framework.test import APIRequestFactory
+from rest_framework.test import APIRequestFactory, URLPatternsTestCase
 from rest_framework.utils import json
 
 factory = APIRequestFactory()
@@ -90,23 +90,10 @@ namespaced_router.register(r'example', MockViewSet, base_name='example')
 
 empty_prefix_router = SimpleRouter()
 empty_prefix_router.register(r'', EmptyPrefixViewSet, base_name='empty_prefix')
-empty_prefix_urls = [
-    url(r'^', include(empty_prefix_router.urls)),
-]
 
 regex_url_path_router = SimpleRouter()
 regex_url_path_router.register(r'', RegexUrlPathViewSet, base_name='regex')
 
-urlpatterns = [
-    url(r'^non-namespaced/', include(namespaced_router.urls)),
-    url(r'^namespaced/', include((namespaced_router.urls, 'example'), namespace='example')),
-    url(r'^example/', include(notes_router.urls)),
-    url(r'^example2/', include(kwarged_notes_router.urls)),
-
-    url(r'^empty-prefix/', include(empty_prefix_urls)),
-    url(r'^regex/', include(regex_url_path_router.urls))
-]
-
 
 class BasicViewSet(viewsets.ViewSet):
     def list(self, request, *args, **kwargs):
@@ -156,8 +143,12 @@ class TestSimpleRouter(TestCase):
                 assert route.mapping[method] == endpoint
 
 
-@override_settings(ROOT_URLCONF='tests.test_routers')
-class TestRootView(TestCase):
+class TestRootView(URLPatternsTestCase, TestCase):
+    urlpatterns = [
+        url(r'^non-namespaced/', include(namespaced_router.urls)),
+        url(r'^namespaced/', include((namespaced_router.urls, 'namespaced'), namespace='namespaced')),
+    ]
+
     def test_retrieve_namespaced_root(self):
         response = self.client.get('/namespaced/')
         assert response.data == {"example": "http://testserver/namespaced/example/"}
@@ -167,11 +158,15 @@ class TestRootView(TestCase):
         assert response.data == {"example": "http://testserver/non-namespaced/example/"}
 
 
-@override_settings(ROOT_URLCONF='tests.test_routers')
-class TestCustomLookupFields(TestCase):
+class TestCustomLookupFields(URLPatternsTestCase, TestCase):
     """
     Ensure that custom lookup fields are correctly routed.
     """
+    urlpatterns = [
+        url(r'^example/', include(notes_router.urls)),
+        url(r'^example2/', include(kwarged_notes_router.urls)),
+    ]
+
     def setUp(self):
         RouterTestModel.objects.create(uuid='123', text='foo bar')
         RouterTestModel.objects.create(uuid='a b', text='baz qux')
@@ -219,12 +214,17 @@ class TestLookupValueRegex(TestCase):
 
 
 @override_settings(ROOT_URLCONF='tests.test_routers')
-class TestLookupUrlKwargs(TestCase):
+class TestLookupUrlKwargs(URLPatternsTestCase, TestCase):
     """
     Ensure the router honors lookup_url_kwarg.
 
     Setup a deep lookup_field, but map it to a simple URL kwarg.
     """
+    urlpatterns = [
+        url(r'^example/', include(notes_router.urls)),
+        url(r'^example2/', include(kwarged_notes_router.urls)),
+    ]
+
     def setUp(self):
         RouterTestModel.objects.create(uuid='123', text='foo bar')
 
@@ -408,8 +408,11 @@ class TestDynamicListAndDetailRouter(TestCase):
         self._test_list_and_detail_route_decorators(SubDynamicListAndDetailViewSet)
 
 
-@override_settings(ROOT_URLCONF='tests.test_routers')
-class TestEmptyPrefix(TestCase):
+class TestEmptyPrefix(URLPatternsTestCase, TestCase):
+    urlpatterns = [
+        url(r'^empty-prefix/', include(empty_prefix_router.urls)),
+    ]
+
     def test_empty_prefix_list(self):
         response = self.client.get('/empty-prefix/')
         assert response.status_code == 200
@@ -422,8 +425,11 @@ class TestEmptyPrefix(TestCase):
         assert json.loads(response.content.decode('utf-8')) == {'uuid': '111', 'text': 'First'}
 
 
-@override_settings(ROOT_URLCONF='tests.test_routers')
-class TestRegexUrlPath(TestCase):
+class TestRegexUrlPath(URLPatternsTestCase, TestCase):
+    urlpatterns = [
+        url(r'^regex/', include(regex_url_path_router.urls)),
+    ]
+
     def test_regex_url_path_list(self):
         kwarg = '1234'
         response = self.client.get('/regex/list/{}/'.format(kwarg))
@@ -438,8 +444,11 @@ class TestRegexUrlPath(TestCase):
         assert json.loads(response.content.decode('utf-8')) == {'pk': pk, 'kwarg': kwarg}
 
 
-@override_settings(ROOT_URLCONF='tests.test_routers')
-class TestViewInitkwargs(TestCase):
+class TestViewInitkwargs(URLPatternsTestCase, TestCase):
+    urlpatterns = [
+        url(r'^example/', include(notes_router.urls)),
+    ]
+
     def test_suffix(self):
         match = resolve('/example/notes/')
         initkwargs = match.func.initkwargs

tests/test_testing.py

@@ -12,7 +12,7 @@ from rest_framework import fields, serializers
 from rest_framework.decorators import api_view
 from rest_framework.response import Response
 from rest_framework.test import (
-    APIClient, APIRequestFactory, force_authenticate
+    APIClient, APIRequestFactory, URLPatternsTestCase, force_authenticate
 )
 
 
@@ -283,3 +283,30 @@ class TestAPIRequestFactory(TestCase):
             content_type='application/json',
         )
         assert request.META['CONTENT_TYPE'] == 'application/json'
+
+
+class TestUrlPatternTestCase(URLPatternsTestCase):
+    urlpatterns = [
+        url(r'^$', view),
+    ]
+
+    @classmethod
+    def setUpClass(cls):
+        assert urlpatterns is not cls.urlpatterns
+        super(TestUrlPatternTestCase, cls).setUpClass()
+        assert urlpatterns is cls.urlpatterns
+
+    @classmethod
+    def tearDownClass(cls):
+        assert urlpatterns is cls.urlpatterns
+        super(TestUrlPatternTestCase, cls).tearDownClass()
+        assert urlpatterns is not cls.urlpatterns
+
+    def test_urlpatterns(self):
+        assert self.client.get('/').status_code == 200
+
+
+class TestExistingPatterns(TestCase):
+    def test_urlpatterns(self):
+        # sanity test to ensure that this test module does not have a '/' route
+        assert self.client.get('/').status_code == 404

tests/test_versioning.py

@@ -7,33 +7,12 @@ from rest_framework.decorators import APIView
 from rest_framework.relations import PKOnlyObject
 from rest_framework.response import Response
 from rest_framework.reverse import reverse
-from rest_framework.test import APIRequestFactory, APITestCase
+from rest_framework.test import (
+    APIRequestFactory, APITestCase, URLPatternsTestCase
+)
 from rest_framework.versioning import NamespaceVersioning
 
 
-@override_settings(ROOT_URLCONF='tests.test_versioning')
-class URLPatternsTestCase(APITestCase):
-    """
-    Isolates URL patterns used during testing on the test class itself.
-    For example:
-
-    class MyTestCase(URLPatternsTestCase):
-        urlpatterns = [
-            ...
-        ]
-
-        def test_something(self):
-            ...
-    """
-    def setUp(self):
-        global urlpatterns
-        urlpatterns = self.urlpatterns
-
-    def tearDown(self):
-        global urlpatterns
-        urlpatterns = []
-
-
 class RequestVersionView(APIView):
     def get(self, request, *args, **kwargs):
         return Response({'version': request.version})
@@ -163,7 +142,7 @@ class TestRequestVersion:
         assert response.data == {'version': None}
 
 
-class TestURLReversing(URLPatternsTestCase):
+class TestURLReversing(URLPatternsTestCase, APITestCase):
     included = [
         url(r'^namespaced/$', dummy_view, name='another'),
         url(r'^example/(?P<pk>\d+)/$', dummy_pk_view, name='example-detail')
@@ -329,7 +308,7 @@ class TestAllowedAndDefaultVersion:
         assert response.data == {'version': 'v2'}
 
 
-class TestHyperlinkedRelatedField(URLPatternsTestCase):
+class TestHyperlinkedRelatedField(URLPatternsTestCase, APITestCase):
     included = [
         url(r'^namespaced/(?P<pk>\d+)/$', dummy_pk_view, name='namespaced'),
     ]
@@ -361,7 +340,7 @@ class TestHyperlinkedRelatedField(URLPatternsTestCase):
             self.field.to_internal_value('/v2/namespaced/3/')
 
 
-class TestNamespaceVersioningHyperlinkedRelatedFieldScheme(URLPatternsTestCase):
+class TestNamespaceVersioningHyperlinkedRelatedFieldScheme(URLPatternsTestCase, APITestCase):
     nested = [
         url(r'^namespaced/(?P<pk>\d+)/$', dummy_pk_view, name='nested'),
     ]