Fixed #26440 -- Added a warning for non-url()s in urlpatterns.

Thanks Burhan Khalid for the initial patch and knbk/timgraham
for review.

2 files changed, 32 insertions, 1 deletions

diff --git a/tests/check_framework/test_urls.py b/tests/check_framework/test_urls.py
index a0c113aac3..a1ac727057 100644
--- a/tests/check_framework/test_urls.py
+++ b/tests/check_framework/test_urls.py
@@ -1,5 +1,7 @@
 from django.conf import settings
-from django.core.checks.urls import check_url_config
+from django.core.checks.urls import (
+    check_url_config, get_warning_for_invalid_pattern,
+)
 from django.test import SimpleTestCase
 from django.test.utils import override_settings
 
@@ -27,6 +29,16 @@ class CheckUrlsTest(SimpleTestCase):
         expected_msg = "Your URL pattern '^include-with-dollar$' uses include with a regex ending with a '$'."
         self.assertIn(expected_msg, warning.msg)
 
+    @override_settings(ROOT_URLCONF='check_framework.urls.contains_tuple')
+    def test_contains_tuple_not_url_instance(self):
+        result = check_url_config(None)
+        warning = result[0]
+        self.assertEqual(warning.id, 'urls.E004')
+        self.assertRegexpMatches(warning.msg, (
+            r"^Your URL pattern \('\^tuple/\$', <function <lambda> at 0x(\w+)>\) is "
+            r"invalid. Ensure that urlpatterns is a list of url\(\) instances.$"
+        ))
+
     @override_settings(ROOT_URLCONF='check_framework.urls.beginning_with_slash')
     def test_beginning_with_slash(self):
         result = check_url_config(None)
@@ -50,3 +62,19 @@ class CheckUrlsTest(SimpleTestCase):
         delattr(settings, 'ROOT_URLCONF')
         result = check_url_config(None)
         self.assertEqual(result, [])
+
+    def test_get_warning_for_invalid_pattern_string(self):
+        warning = get_warning_for_invalid_pattern('')[0]
+        self.assertEqual(
+            warning.hint,
+            "Try removing the string ''. The list of urlpatterns should "
+            "not have a prefix string as the first element.",
+        )
+
+    def test_get_warning_for_invalid_pattern_tuple(self):
+        warning = get_warning_for_invalid_pattern((r'^$', lambda x: x))[0]
+        self.assertEqual(warning.hint, "Try using url() instead of a tuple.")
+
+    def test_get_warning_for_invalid_pattern_other(self):
+        warning = get_warning_for_invalid_pattern(object())[0]
+        self.assertIsNone(warning.hint)
diff --git a/tests/check_framework/urls/contains_tuple.py b/tests/check_framework/urls/contains_tuple.py
new file mode 100644
index 0000000000..56aa3ea364
--- /dev/null
+++ b/tests/check_framework/urls/contains_tuple.py
@@ -0,0 +1,3 @@
+urlpatterns = [
+    (r'^tuple/$', lambda x: x),
+]