Fixed #16362 -- Allowed lookaround assertions in URL patterns.

2 files changed, 51 insertions, 0 deletions

diff --git a/tests/urlpatterns_reverse/tests.py b/tests/urlpatterns_reverse/tests.py
index eca5bc1e64..8706c64b64 100644
--- a/tests/urlpatterns_reverse/tests.py
+++ b/tests/urlpatterns_reverse/tests.py
@@ -799,3 +799,50 @@ class IncludeTests(SimpleTestCase):
         msg = "Must specify a namespace if specifying app_name."
         with self.assertRaisesMessage(ValueError, msg):
             include('urls', app_name='bar')
+
+
+@override_settings(ROOT_URLCONF='urlpatterns_reverse.urls')
+class LookaheadTests(TestCase):
+    def test_valid_resolve(self):
+        test_urls = [
+            '/lookahead-/a-city/',
+            '/lookbehind-/a-city/',
+            '/lookahead+/a-city/',
+            '/lookbehind+/a-city/',
+        ]
+        for test_url in test_urls:
+            match = resolve(test_url)
+            self.assertEqual(match.kwargs, {'city': 'a-city'})
+
+    def test_invalid_resolve(self):
+        test_urls = [
+            '/lookahead-/not-a-city/',
+            '/lookbehind-/not-a-city/',
+            '/lookahead+/other-city/',
+            '/lookbehind+/other-city/',
+        ]
+        for test_url in test_urls:
+            with self.assertRaises(Resolver404):
+                resolve(test_url)
+
+    def test_valid_reverse(self):
+        url = reverse('lookahead-positive', kwargs={'city': 'a-city'})
+        self.assertEqual(url, '/lookahead+/a-city/')
+        url = reverse('lookahead-negative', kwargs={'city': 'a-city'})
+        self.assertEqual(url, '/lookahead-/a-city/')
+
+        url = reverse('lookbehind-positive', kwargs={'city': 'a-city'})
+        self.assertEqual(url, '/lookbehind+/a-city/')
+        url = reverse('lookbehind-negative', kwargs={'city': 'a-city'})
+        self.assertEqual(url, '/lookbehind-/a-city/')
+
+    def test_invalid_reverse(self):
+        with self.assertRaises(NoReverseMatch):
+            reverse('lookahead-positive', kwargs={'city': 'other-city'})
+        with self.assertRaises(NoReverseMatch):
+            reverse('lookahead-negative', kwargs={'city': 'not-a-city'})
+
+        with self.assertRaises(NoReverseMatch):
+            reverse('lookbehind-positive', kwargs={'city': 'other-city'})
+        with self.assertRaises(NoReverseMatch):
+            reverse('lookbehind-negative', kwargs={'city': 'not-a-city'})
diff --git a/tests/urlpatterns_reverse/urls.py b/tests/urlpatterns_reverse/urls.py
index d6b692d220..25609c14cf 100644
--- a/tests/urlpatterns_reverse/urls.py
+++ b/tests/urlpatterns_reverse/urls.py
@@ -62,6 +62,10 @@ with warnings.catch_warnings():
         url(r'^outer/(?P<outer>[0-9]+)/', include('urlpatterns_reverse.included_urls')),
         url(r'^outer-no-kwargs/([0-9]+)/', include('urlpatterns_reverse.included_no_kwargs_urls')),
         url('', include('urlpatterns_reverse.extra_urls')),
+        url(r'^lookahead-/(?!not-a-city)(?P<city>[^/]+)/$', empty_view, name='lookahead-negative'),
+        url(r'^lookahead\+/(?=a-city)(?P<city>[^/]+)/$', empty_view, name='lookahead-positive'),
+        url(r'^lookbehind-/(?P<city>[^/]+)(?<!not-a-city)/$', empty_view, name='lookbehind-negative'),
+        url(r'^lookbehind\+/(?P<city>[^/]+)(?<=a-city)/$', empty_view, name='lookbehind-positive'),
 
         # Partials should be fine.
         url(r'^partial/', empty_view_partial, name="partial"),