ENT-320: Fix OAuth2ProviderConfig to be keyed by `provider_slug`

This change fixes a bug where OAuth2 Provider Configs only show
up on logistration if the provider's `provider_slug` matches a
valid OAuth2 backend name.

Closes ENT-320.

common/djangoapps/third_party_auth/admin.py

@@ -33,7 +33,7 @@ class OAuth2ProviderConfigAdmin(KeyedConfigurationModelAdmin):
     def get_list_display(self, request):
         """ Don't show every single field in the admin change list """
         return (
-            'name', 'enabled', 'site', 'backend_name', 'secondary', 'skip_registration_form',
+            'name', 'enabled', 'provider_slug', 'site', 'backend_name', 'secondary', 'skip_registration_form',
             'skip_email_verification', 'change_date', 'changed_by', 'edit_link',
         )
 

common/djangoapps/third_party_auth/provider.py

@@ -22,9 +22,10 @@ class Registry(object):
         Helper method that returns a generator used to iterate over all providers
         of the current site.
         """
-        for backend_name in _PSA_OAUTH2_BACKENDS:
-            provider = OAuth2ProviderConfig.current(backend_name)
-            if provider.enabled_for_current_site:
+        oauth2_slugs = OAuth2ProviderConfig.key_values('provider_slug', flat=True)
+        for oauth2_slug in oauth2_slugs:
+            provider = OAuth2ProviderConfig.current(oauth2_slug)
+            if provider.enabled_for_current_site and provider.backend_name in _PSA_OAUTH2_BACKENDS:
                 yield provider
         if SAMLConfiguration.is_enabled(Site.objects.get_current(get_current_request())):
             idp_slugs = SAMLProviderConfig.key_values('idp_slug', flat=True)
@@ -103,9 +104,11 @@ class Registry(object):
             Instances of ProviderConfig.
         """
         if backend_name in _PSA_OAUTH2_BACKENDS:
-            provider = OAuth2ProviderConfig.current(backend_name)
-            if provider.enabled_for_current_site:
-                yield provider
+            oauth2_slugs = OAuth2ProviderConfig.key_values('provider_slug', flat=True)
+            for oauth2_slug in oauth2_slugs:
+                provider = OAuth2ProviderConfig.current(oauth2_slug)
+                if provider.backend_name == backend_name and provider.enabled_for_current_site:
+                    yield provider
         elif backend_name in _PSA_SAML_BACKENDS and SAMLConfiguration.is_enabled(
                 Site.objects.get_current(get_current_request())):
             idp_names = SAMLProviderConfig.key_values('idp_slug', flat=True)

common/djangoapps/third_party_auth/tests/test_provider.py

@@ -148,6 +148,24 @@ class RegistryTest(testutil.TestCase):
         google_provider = self.configure_google_provider(enabled=True)
         self.assertEqual(google_provider.id, provider.Registry.get(google_provider.provider_id).id)
 
+    def test_oauth2_provider_keyed_by_provider_slug(self):
+        """
+        Regression test to ensure that the Registry properly fetches OAuth2ProviderConfigs that have a provider_slug
+        which doesn't match any of the possible backend_names.
+        """
+        google_provider = self.configure_google_provider(enabled=True, provider_slug='custom_slug')
+        self.assertIn(google_provider, provider.Registry._enabled_providers())
+        self.assertIn(google_provider, provider.Registry.get_enabled_by_backend_name('google-oauth2'))
+
+    def test_oauth2_enabled_only_for_supplied_backend(self):
+        """
+        Test to ensure that Registry.get_enabled_by_backend_name doesn't return OAuth2 providers with incorrect
+        backend_names.
+        """
+        facebook_provider = self.configure_facebook_provider(enabled=True)
+        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_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