Merge pull request #17223 from edx/douglashall/ENT-851

ENT-851 TPA Registry.get should return None if passed None.

common/djangoapps/third_party_auth/provider.py

@@ -71,6 +71,8 @@ class Registry(object):
     @classmethod
     def get(cls, provider_id):
         """Gets provider by provider_id string if enabled, else None."""
+        if not provider_id:
+            return None
         if '-' not in provider_id:  # Check format - see models.py:ProviderConfig
             raise ValueError("Invalid provider_id. Expect something like oa2-google")
         try:

common/djangoapps/third_party_auth/tests/test_provider.py

@@ -168,6 +168,9 @@ class RegistryTest(testutil.TestCase):
         self.configure_google_provider(enabled=True)
         self.assertNotIn(facebook_provider, provider.Registry.get_enabled_by_backend_name('google-oauth2'))
 
+    def test_get_returns_none_if_provider_id_is_none(self):
+        self.assertIsNone(provider.Registry.get(None))
+
     def test_get_returns_none_if_provider_not_enabled(self):
         linkedin_provider_id = "oa2-linkedin-oauth2"
         # At this point there should be no configuration entries at all so no providers should be enabled