Fixed #25187 -- Made request available in authentication backends.

tests/auth_tests/test_auth_backends_deprecation.py

@@ -0,0 +1,30 @@
+import warnings
+
+from django.contrib.auth import authenticate
+from django.test import SimpleTestCase, override_settings
+
+
+class NoRequestBackend(object):
+    def authenticate(self, username=None, password=None):
+        # Doesn't accept a request parameter.
+        pass
+
+
+class AcceptsRequestBackendTest(SimpleTestCase):
+    """
+    A deprecation warning is shown for backends that have an authenticate()
+    method without a request parameter.
+    """
+    no_request_backend = '%s.NoRequestBackend' % __name__
+
+    @override_settings(AUTHENTICATION_BACKENDS=[no_request_backend])
+    def test_no_request_deprecation_warning(self):
+        with warnings.catch_warnings(record=True) as warns:
+            warnings.simplefilter('always')
+            authenticate(username='test', password='test')
+        self.assertEqual(len(warns), 1)
+        self.assertEqual(
+            str(warns[0].message),
+            "Update authentication backend %s to accept a positional `request` "
+            "argument." % self.no_request_backend
+        )