diff --git a/common/lib/xmodule/tests/__init__.py b/common/lib/xmodule/tests/__init__.py
index 5483015a82..2f12c96a7a 100644
--- a/common/lib/xmodule/tests/__init__.py
+++ b/common/lib/xmodule/tests/__init__.py
@@ -13,6 +13,7 @@ import numpy
 import xmodule
 import capa.calc as calc
 import capa.capa_problem as lcp
+from capa.correctmap import CorrectMap
 from xmodule import graders, x_module
 from xmodule.graders import Score, aggregate_scores
 from xmodule.progress import Progress
@@ -271,6 +272,50 @@ class StringResponseWithHintTest(unittest.TestCase):
         self.assertEquals(cmap.get_correctness('1_2_1'), 'incorrect')
         self.assertTrue('St. Paul' in cmap.get_hint('1_2_1'))
 
+class CodeResponseTest(unittest.TestCase):
+    '''
+    Test CodeResponse
+
+    '''
+    def test_update_score(self):
+        problem_file = os.path.dirname(__file__)+"/test_files/coderesponse.xml"
+        test_lcp = lcp.LoncapaProblem(open(problem_file).read(), '1', system=i4xs)
+        
+        # CodeResponse requires internal CorrectMap state. Build it now
+        old_cmap = CorrectMap()
+        answer_ids = sorted(test_lcp.get_question_answers().keys())
+        numAnswers = len(answer_ids)
+        for i in range(numAnswers):
+            old_cmap.update(CorrectMap(answer_id=answer_ids[i], queuekey=1000+i))
+
+        # Message format inherited from ExternalResponse
+        correct_score_msg   = "<edxgrade><awarddetail>EXACT_ANS</awarddetail><message>MESSAGE</message></edxgrade>"
+        incorrect_score_msg = "<edxgrade><awarddetail>WRONG_FORMAT</awarddetail><message>MESSAGE</message></edxgrade>" 
+        xserver_msgs = {'correct':   correct_score_msg,
+                        'incorrect': incorrect_score_msg, 
+                        }
+
+        # Incorrect queuekey, state should not be updated
+        for correctness in ['correct', 'incorrect']:
+            test_lcp.correct_map = CorrectMap() 
+            test_lcp.correct_map.update(old_cmap) # Deep copy
+
+            test_lcp.update_score(xserver_msgs[correctness], queuekey=0)
+            self.assertEquals(test_lcp.correct_map.get_dict(), old_cmap.get_dict()) # Deep comparison
+
+        # Correct queuekey, state should be updated
+        for correctness in ['correct', 'incorrect']:
+            for i in range(numAnswers): # Target specific answer_id's
+                test_lcp.correct_map = CorrectMap() 
+                test_lcp.correct_map.update(old_cmap)
+
+                new_cmap = CorrectMap()
+                new_cmap.update(old_cmap)
+                new_cmap.set(answer_id=answer_ids[i], correctness=correctness, msg='MESSAGE', queuekey=None)
+
+                test_lcp.update_score(xserver_msgs[correctness], queuekey=1000+i)
+                self.assertEquals(test_lcp.correct_map.get_dict(), new_cmap.get_dict())
+
 #-----------------------------------------------------------------------------
 # Grading tests
 
diff --git a/common/lib/xmodule/tests/test_files/coderesponse.xml b/common/lib/xmodule/tests/test_files/coderesponse.xml
new file mode 100644
index 0000000000..42b6e0a54a
--- /dev/null
+++ b/common/lib/xmodule/tests/test_files/coderesponse.xml
@@ -0,0 +1,101 @@
+<problem>
+<text>
+<h2>Code response</h2>
+
+<p>
+</p>
+
+<text>
+Write a program to compute the square of a number
+  <coderesponse tests="repeat:2,generate">
+    <textbox rows="10" cols="70"  mode="python"/>
+    <answer><![CDATA[
+initial_display = """
+def square(n):
+"""
+
+answer = """
+def square(n):
+    return n**2    
+"""
+
+preamble = """ 
+import sys, time
+"""
+
+test_program = """
+import random
+import operator
+
+def testSquare(n = None):
+    if n is None:
+       n = random.randint(2, 20)
+    print 'Test is: square(%d)'%n
+    return str(square(n))
+
+def main():
+   f = os.fdopen(3,'w')
+   test = int(sys.argv[1])
+   rndlist = map(int,os.getenv('rndlist').split(','))
+   random.seed(rndlist[0])
+   if test == 1: f.write(testSquare(0))
+   elif test == 2: f.write(testSquare(1))
+   else:  f.write(testSquare())
+   f.close()
+
+main()
+sys.exit(0)
+"""
+]]>
+    </answer>
+  </coderesponse>
+</text>
+
+<text>
+Write a program to compute the cube of a number
+  <coderesponse tests="repeat:2,generate">
+    <textbox rows="10" cols="70"  mode="python"/>
+    <answer><![CDATA[
+initial_display = """
+def cube(n):
+"""
+
+answer = """
+def cube(n):
+    return n**3    
+"""
+
+preamble = """ 
+import sys, time
+"""
+
+test_program = """
+import random
+import operator
+
+def testCube(n = None):
+    if n is None:
+       n = random.randint(2, 20)
+    print 'Test is: cube(%d)'%n
+    return str(cube(n))
+
+def main():
+   f = os.fdopen(3,'w')
+   test = int(sys.argv[1])
+   rndlist = map(int,os.getenv('rndlist').split(','))
+   random.seed(rndlist[0])
+   if test == 1: f.write(testCube(0))
+   elif test == 2: f.write(testCube(1))
+   else:  f.write(testCube())
+   f.close()
+
+main()
+sys.exit(0)
+"""
+]]>
+    </answer>
+  </coderesponse>
+</text>
+
+</text>
+</problem>