Have external login always make an API request to get the authorization URL

This makes the OIDC lookup lazy, ensuring that the rest of the registry and app continues working even if one OIDC provider goes down.

test/test_api_security.py

@@ -28,7 +28,7 @@ from endpoints.api.repositorynotification import RepositoryNotification, Reposit
 from endpoints.api.user import (PrivateRepositories, ConvertToOrganization, Recovery, Signout,
                                 Signin, User, UserAuthorizationList, UserAuthorization, UserNotification,
                                 VerifyUser, DetachExternal, StarredRepositoryList, StarredRepository,
-                                ClientKey)
+                                ClientKey, ExternalLoginInformation)
 from endpoints.api.repotoken import RepositoryToken, RepositoryTokenList
 from endpoints.api.prototype import PermissionPrototype, PermissionPrototypeList
 from endpoints.api.logs import UserLogs, OrgLogs, RepositoryLogs
@@ -504,6 +504,24 @@ class TestSignin(ApiTestCase):
     self._run_test('POST', 403, 'devtable', {u'username': 'E9RY', u'password': 'LQ0N'})
 
 
+class TestExternalLoginInformation(ApiTestCase):
+  def setUp(self):
+    ApiTestCase.setUp(self)
+    self._set_url(ExternalLoginInformation, service_id='someservice')
+
+  def test_post_anonymous(self):
+    self._run_test('POST', 400, None, {})
+
+  def test_post_freshuser(self):
+    self._run_test('POST', 400, 'freshuser', {})
+
+  def test_post_reader(self):
+    self._run_test('POST', 400, 'reader', {})
+
+  def test_post_devtable(self):
+    self._run_test('POST', 400, 'devtable', {})
+
+
 class TestDetachExternal(ApiTestCase):
   def setUp(self):
     ApiTestCase.setUp(self)