Address review comments

common/test/data/open_ended_nopath/README.md

+This is a very very simple course, useful for debugging open ended grading code.  This is specifically for testing if a peer grading module with no path to it in the course will be handled properly.

common/test/data/open_ended_nopath/course.xml

+<course org="edX" course="open_ended_nopath" url_name="2012_Fall"/>

common/test/data/open_ended_nopath/course/2012_Fall.xml

+<course>
+  <chapter url_name="Overview">
+  </chapter>
+</course>

common/test/data/open_ended_nopath/peergrading/PeerGradingNoPath.xml

+<peergrading/>
\ No newline at end of file

common/test/data/open_ended_nopath/policies/2012_Fall.json

+{
+    "course/2012_Fall": {
+        "graceperiod": "2 days 5 hours 59 minutes 59 seconds",
+        "start": "2015-07-17T12:00",
+        "display_name": "Self Assessment Test",
+        "graded": "true"
+    },
+    "chapter/Overview": {
+        "display_name": "Overview"
+    }
+}

lms/djangoapps/courseware/tests/modulestore_config.py

@@ -22,5 +22,6 @@ MAPPINGS = {
     'edX/test_about_blob_end_date/2012_Fall': 'xml',
     'edX/graded/2012_Fall': 'xml',
     'edX/open_ended/2012_Fall': 'xml',
+    'edX/open_ended_nopath/2012_Fall': 'xml',
 }
 TEST_DATA_MIXED_MODULESTORE = mixed_store_config(TEST_DATA_DIR, MAPPINGS)

lms/djangoapps/open_ended_grading/tests.py

@@ -320,3 +320,22 @@ class TestPanel(ModuleStoreTestCase, LoginEnrollmentTestCase):
         request = Mock(user=self.user)
         response = views.student_problem_list(request, self.course.id)
         self.assertRegexpMatches(response.content, "Here are a list of open ended problems for this course.")
+
+@override_settings(MODULESTORE=TEST_DATA_MIXED_MODULESTORE)
+class TestPeerGradingFound(ModuleStoreTestCase):
+    """
+    Test to see if peer grading modules can be found properly.
+    """
+
+    def setUp(self):
+        self.course_name = 'edX/open_ended_nopath/2012_Fall'
+        self.course = modulestore().get_course(self.course_name)
+
+    def test_peer_grading_nopath(self):
+        """
+        The open_ended_nopath course contains a peer grading module with no path to it.
+        Ensure that the exception is caught.
+        """
+
+        found, url = views.find_peer_grading_module(self.course)
+        self.assertEqual(found, False)
\ No newline at end of file

lms/djangoapps/open_ended_grading/views.py

@@ -97,28 +97,31 @@ def find_peer_grading_module(course):
     @param course: A course object.
     @return: boolean found_module, string problem_url
     """
-    #Reverse the base course url
+
+    # Reverse the base course url.
     base_course_url = reverse('courses')
     found_module = False
     problem_url = ""
 
-    #Get the course id and split it
+    # Get the course id and split it.
     course_id_parts = course.id.split("/")
     log.info("COURSE ID PARTS")
     log.info(course_id_parts)
-    #Get the peer grading modules currently in the course.  Explicitly specify the course id to avoid issues with different runs.
+    # Get the peer grading modules currently in the course.  Explicitly specify the course id to avoid issues with different runs.
     items = modulestore().get_items(['i4x', course_id_parts[0], course_id_parts[1], 'peergrading', None],
                                     course_id=course.id)
     #See if any of the modules are centralized modules (ie display info from multiple problems)
     items = [i for i in items if not getattr(i, "use_for_single_location", True)]
-    #Get the first one
+    # Loop through all potential peer grading modules, and find the first one that has a path to it.
     for item in items:
         item_location = item.location
-        #Generate a url for the first module and redirect the user to it
+        # Generate a url for the first module and redirect the user to it.
         try:
             problem_url_parts = search.path_to_location(modulestore(), course.id, item_location)
         except NoPathToItem:
-            log.info("Invalid peer grading module location {0} in course {1}.".format(item_location, course.id))
+            # In the case of nopathtoitem, the peer grading module that was found is in an invalid state, and
+            # can no longer be accessed.  Log an informational message, but this will not impact normal behavior.
+            log.info("Invalid peer grading module location {0} in course {1}.  This module may need to be removed.".format(item_location, course.id))
             continue
         problem_url = generate_problem_url(problem_url_parts, base_course_url)
         found_module = True