External_auth.views.login_or_signup fix codepath that didn't set uname

which caused UnboundLocalError.  Added tests for this case

Conflicts:
	common/djangoapps/external_auth/tests/test_shib.py

common/djangoapps/external_auth/tests/test_shib.py

@@ -73,8 +73,14 @@ class ShibSPTest(ModuleStoreTestCase):
     @unittest.skipUnless(settings.MITX_FEATURES.get('AUTH_USE_SHIB'), True)
     def test_shib_login(self):
         """
-        Tests that a user with a shib ExternalAuthMap gets logged in while when
-        shib-login is called, while a user without such gets the registration form.
+        Tests that:
+          * shib credentials that match an existing ExternalAuthMap with a linked active user logs the user in
+          * shib credentials that match an existing ExternalAuthMap with a linked inactive user shows error page
+          * shib credentials that match an existing ExternalAuthMap without a linked user and also match the email
+            of an existing user without an existing ExternalAuthMap links the two and log the user in
+          * shib credentials that match an existing ExternalAuthMap without a linked user and also match the email
+            of an existing user that already has an ExternalAuthMap causes an error (403)
+          * shib credentials that do not match an existing ExternalAuthMap causes the registration form to appear
         """
 
         student = UserFactory.create()
@@ -86,8 +92,19 @@ class ShibSPTest(ModuleStoreTestCase):
         student.save()
         extauth.save()
 
+        inactive_user = UserFactory.create(email='inactive@stanford.edu')
+        inactive_user.is_active = False
+        inactive_extauth = ExternalAuthMap(external_id='inactive@stanford.edu',
+                                           external_email='',
+                                           external_domain='shib:https://idp.stanford.edu/',
+                                           external_credentials="",
+                                           user=inactive_user)
+        inactive_user.save()
+        inactive_extauth.save()
+
         idps = ['https://idp.stanford.edu/', 'https://someother.idp.com/']
-        remote_users = ['testuser@stanford.edu', 'testuser2@someother_idp.com']
+        remote_users = ['withmap@stanford.edu', 'womap@stanford.edu',
+                        'testuser2@someother_idp.com', 'inactive@stanford.edu']
 
         for idp in idps:
             for remote_user in remote_users:
@@ -101,6 +118,18 @@ class ShibSPTest(ModuleStoreTestCase):
                     self.assertIsInstance(response, HttpResponseRedirect)
                     self.assertEqual(request.user, student)
                     self.assertEqual(response['Location'], '/')
+                elif idp == "https://idp.stanford.edu/" and remote_user == 'inactive@stanford.edu':
+                    self.assertEqual(response.status_code, 403)
+                    self.assertIn("Account not yet activated: please look for link in your email", response.content)
+                elif idp == "https://idp.stanford.edu/" and remote_user == 'womap@stanford.edu':
+                    self.assertIsNotNone(ExternalAuthMap.objects.get(user=user_wo_map))
+                    self.assertIsInstance(response, HttpResponseRedirect)
+                    self.assertEqual(request.user, user_wo_map)
+                    self.assertEqual(response['Location'], '/')
+                elif idp == "https://someother.idp.com/" and remote_user in \
+                            ['withmap@stanford.edu', 'womap@stanford.edu', 'inactive@stanford.edu']:
+                    self.assertEqual(response.status_code, 403)
+                    self.assertIn("You have already created an account using an external login", response.content)
                 else:
                     self.assertEqual(response.status_code, 200)
                     self.assertContains(response, "<title>Register for")

common/djangoapps/external_auth/views.py

@@ -173,6 +173,7 @@ def external_login_or_signup(request,
 
     # We trust shib's authentication, so no need to authenticate using the password again
     if settings.MITX_FEATURES.get('AUTH_USE_SHIB'):
+        uname = internal_user.username
         user = internal_user
         # Assuming this 'AUTHENTICATION_BACKENDS' is set in settings, which I think is safe
         if settings.AUTHENTICATION_BACKENDS: