update_score: edit existing CorrectMap rather than starting with empty CorrectMap

common/lib/capa/capa/capa_problem.py

@@ -22,6 +22,7 @@ import random
 import re
 import scipy
 import struct
+import json
 
 from lxml import etree
 from xml.sax.saxutils import unescape
@@ -186,14 +187,13 @@ class LoncapaProblem(object):
          
         Returns an updated CorrectMap
         '''
-        oldcmap = self.correct_map
-        newcmap = CorrectMap()
+        cmap = self.correct_map
         for responder in self.responders.values():
             if hasattr(responder,'update_score'): # TODO: Is this the best way to target 'update_score' of CodeResponse?
-                results = responder.update_score(score_msg, oldcmap, queuekey)
-                newcmap.update(results)
-        self.correct_map = newcmap
-        return newcmap
+                # Each LoncapaResponse will update the specific entries of 'cmap' that it's responsible for
+                cmap = responder.update_score(score_msg, cmap, queuekey)
+        self.correct_map = cmap
+        return cmap 
 
     def is_queued(self):
         '''

common/lib/capa/capa/responsetypes.py

@@ -695,8 +695,9 @@ class SymbolicResponse(CustomResponse):
 
 class CodeResponse(LoncapaResponse):
     ''' 
-    Grade student code using an external server. Unlike ExternalResponse, CodeResponse:
-        1) Goes through a queueing system (xqueue)
+    Grade student code using an external server, called 'xqueue'
+    In contrast to ExternalResponse, CodeResponse has following behavior:
+        1) Goes through a queueing system
         2) Does not do external request for 'get_answers'
     '''
 
@@ -740,7 +741,7 @@ class CodeResponse(LoncapaResponse):
         # Non-null CorrectMap['queuekey'] indicates that the problem has been submitted
         cmap = CorrectMap()
         for answer_id in idset:
-            cmap.set(answer_id, queuekey=queuekey)
+            cmap.set(answer_id, queuekey=queuekey, msg='Submitted to queue')
 
         return cmap
 
@@ -804,7 +805,7 @@ class CodeResponse(LoncapaResponse):
         queuekey = random.randint(0,2**32-1)
         header.update({'queuekey': queuekey})
 
-        payload = {'xqueue_header': json.dumps(header), # TODO: 'xqueue_header' should eventually be derived from config file
+        payload = {'xqueue_header': json.dumps(header), # TODO: 'xqueue_header' should eventually be derived from a config file
                    'xml': xmlstr,
                    'edX_cmd': 'get_score',
                    'edX_tests': self.tests,