Merge pull request #1058 from edx/fix/vik/oe-staff-error

Fix OE AJAX post error

lms/djangoapps/open_ended_grading/staff_grading_service.py

@@ -264,15 +264,26 @@ def get_problem_list(request, course_id):
             min_for_ml: the number of responses that need to be graded before
                 the ml can be run
 
+        'error': if success is False, will have an error message with more info.
     """
     _check_access(request.user, course_id)
     try:
         response = staff_grading_service().get_problem_list(course_id, unique_id_for_user(request.user))
         response = json.loads(response)
-        problem_list = response['problem_list']
+
+        # If 'problem_list' is in the response, then we got a list of problems from the ORA server.
+        # If it is not, then ORA could not find any problems.
+        if 'problem_list' in response:
+            problem_list = response['problem_list']
+        else:
+            problem_list = []
+            # Make an error messages to reflect that we could not find anything to grade.
+            response['error'] = ("Cannot find any open response problems in this course.  "
+                                 "Have you submitted answers to any open response assessment questions?  "
+                                 "If not, please do so and return to this page.")
         valid_problem_list = []
         for i in xrange(0,len(problem_list)):
-            #Needed to ensure that the 'location' key can be accessed
+            # Needed to ensure that the 'location' key can be accessed.
             try:
                 problem_list[i] = json.loads(problem_list[i])
             except Exception:

lms/djangoapps/open_ended_grading/tests.py

@@ -34,6 +34,17 @@ from courseware.tests import factories
 from courseware.tests.modulestore_config import TEST_DATA_MIXED_MODULESTORE
 from courseware.tests.helpers import LoginEnrollmentTestCase, check_for_get_code, check_for_post_code
 
+class EmptyStaffGradingService(object):
+    """
+    A staff grading service that does not return a problem list from get_problem_list.
+    Used for testing to see if error message for empty problem list is correctly displayed.
+    """
+
+    def get_problem_list(self, course_id, user_id):
+        """
+        Return a staff grading response that is missing a problem list key.
+        """
+        return json.dumps({'success': True, 'error': 'No problems found.'})
 
 @override_settings(MODULESTORE=TEST_DATA_MIXED_MODULESTORE)
 class TestStaffGradingService(ModuleStoreTestCase, LoginEnrollmentTestCase):
@@ -134,8 +145,29 @@ class TestStaffGradingService(ModuleStoreTestCase, LoginEnrollmentTestCase):
         response = check_for_post_code(self, 200, url, data)
         content = json.loads(response.content)
 
-        self.assertTrue(content['success'], str(content))
-        self.assertIsNotNone(content['problem_list'])
+        self.assertTrue(content['success'])
+        self.assertEqual(content['problem_list'], [])
+
+    @patch('open_ended_grading.staff_grading_service._service', EmptyStaffGradingService())
+    def test_get_problem_list_missing(self):
+        """
+        Test to see if a staff grading response missing a problem list is given the appropriate error.
+        Mock the staff grading service to enable the key to be missing.
+        """
+
+        # Get a valid user object.
+        instructor = User.objects.get(email=self.instructor)
+        # Mock a request object.
+        request = Mock(
+            user=instructor,
+        )
+        # Get the response and load its content.
+        response = json.loads(staff_grading_service.get_problem_list(request, self.course_id).content)
+
+        # A valid response will have an "error" key.
+        self.assertTrue('error' in response)
+        # Check that the error text is correct.
+        self.assertIn("Cannot find", response['error'])
 
 
 @override_settings(MODULESTORE=TEST_DATA_MIXED_MODULESTORE)