Fixed #27648 -- Deprecated (iLmsu) regex groups in url() patterns.

tests/urlpatterns_reverse/test_deprecated.py

@@ -0,0 +1,33 @@
+import warnings
+
+from django.conf.urls import url
+from django.test import SimpleTestCase, override_settings
+from django.urls import reverse
+
+from .views import empty_view
+
+urlpatterns = [
+    url(r'^(?i)CaseInsensitive/(\w+)', empty_view, name="insensitive"),
+    url(r'^(?i)test/2/?$', empty_view, name="test2"),
+]
+
+
+@override_settings(ROOT_URLCONF='urlpatterns_reverse.test_deprecated')
+class URLPatternReverse(SimpleTestCase):
+
+    def test_urlpattern_reverse(self):
+        test_data = (
+            ('insensitive', '/CaseInsensitive/fred', ['fred'], {}),
+            ('test2', '/test/2', [], {}),
+        )
+        with warnings.catch_warnings(record=True) as warns:
+            warnings.simplefilter('always')
+            warnings.filterwarnings(
+                'ignore', 'Flags not at the start',
+                DeprecationWarning, module='django.urls.resolvers'
+            )
+            for i, (name, expected, args, kwargs) in enumerate(test_data):
+                got = reverse(name, args=args, kwargs=kwargs)
+                self.assertEqual(got, expected)
+                msg = str(warns[i].message)
+                self.assertEqual(msg, 'Using (?i) in url() patterns is deprecated.')