Don't reach in to default value.

common/lib/xmodule/xmodule/course_module.py

@@ -233,7 +233,8 @@ class CourseDescriptor(CourseFields, SequenceDescriptor):
         self._grading_policy = {}
 
         self.set_grading_policy(self.grading_policy)
-        CourseFields.discussion_topics._default = {'General': {'id': self.location.html_id()}}
+        if self.discussion_topics == {}:
+            self.discussion_topics = {'General': {'id': self.location.html_id()}}
 
         self.test_center_exams = []
         test_center_info = self.testcenter_info

common/lib/xmodule/xmodule/tests/test_course_module.py

@@ -40,21 +40,7 @@ class DummySystem(ImportSystem):
         )
 
 
-class IsNewCourseTestCase(unittest.TestCase):
-    """Make sure the property is_new works on courses"""
-
-    def setUp(self):
-        # Needed for test_is_newish
-        datetime_patcher = patch.object(
-            xmodule.course_module, 'datetime',
-            Mock(wraps=datetime.datetime)
-        )
-        mocked_datetime = datetime_patcher.start()
-        mocked_datetime.utcnow.return_value = time_to_datetime(NOW)
-        self.addCleanup(datetime_patcher.stop)
-
-    @staticmethod
-    def get_dummy_course(start, announcement=None, is_new=None, advertised_start=None, end=None):
+def get_dummy_course(start, announcement=None, is_new=None, advertised_start=None, end=None):
     """Get a dummy course"""
 
     system = DummySystem(load_error_modules=True)
@@ -84,6 +70,20 @@ class IsNewCourseTestCase(unittest.TestCase):
 
     return system.process_xml(start_xml)
 
+
+class IsNewCourseTestCase(unittest.TestCase):
+    """Make sure the property is_new works on courses"""
+
+    def setUp(self):
+        # Needed for test_is_newish
+        datetime_patcher = patch.object(
+            xmodule.course_module, 'datetime',
+            Mock(wraps=datetime.datetime)
+        )
+        mocked_datetime = datetime_patcher.start()
+        mocked_datetime.utcnow.return_value = time_to_datetime(NOW)
+        self.addCleanup(datetime_patcher.stop)
+
     @patch('xmodule.course_module.time.gmtime')
     def test_sorting_score(self, gmtime_mock):
         gmtime_mock.return_value = NOW
@@ -120,8 +120,8 @@ class IsNewCourseTestCase(unittest.TestCase):
         ]
 
         for a, b, assertion in dates:
-            a_score = self.get_dummy_course(start=a[0], announcement=a[1], advertised_start=a[2]).sorting_score
-            b_score = self.get_dummy_course(start=b[0], announcement=b[1], advertised_start=b[2]).sorting_score
+            a_score = get_dummy_course(start=a[0], announcement=a[1], advertised_start=a[2]).sorting_score
+            b_score = get_dummy_course(start=b[0], announcement=b[1], advertised_start=b[2]).sorting_score
             print "Comparing %s to %s" % (a, b)
             assertion(a_score, b_score)
 
@@ -138,40 +138,42 @@ class IsNewCourseTestCase(unittest.TestCase):
         ]
 
         for s in settings:
-            d = self.get_dummy_course(start=s[0], advertised_start=s[1])
+            d = get_dummy_course(start=s[0], advertised_start=s[1])
             print "Checking start=%s advertised=%s" % (s[0], s[1])
             self.assertEqual(d.start_date_text, s[2])
 
     def test_is_newish(self):
-        descriptor = self.get_dummy_course(start='2012-12-02T12:00', is_new=True)
+        descriptor = get_dummy_course(start='2012-12-02T12:00', is_new=True)
         assert(descriptor.is_newish is True)
 
-        descriptor = self.get_dummy_course(start='2013-02-02T12:00', is_new=False)
+        descriptor = get_dummy_course(start='2013-02-02T12:00', is_new=False)
         assert(descriptor.is_newish is False)
 
-        descriptor = self.get_dummy_course(start='2013-02-02T12:00', is_new=True)
+        descriptor = get_dummy_course(start='2013-02-02T12:00', is_new=True)
         assert(descriptor.is_newish is True)
 
-        descriptor = self.get_dummy_course(start='2013-01-15T12:00')
+        descriptor = get_dummy_course(start='2013-01-15T12:00')
         assert(descriptor.is_newish is True)
 
-        descriptor = self.get_dummy_course(start='2013-03-01T12:00')
+        descriptor = get_dummy_course(start='2013-03-01T12:00')
         assert(descriptor.is_newish is True)
 
-        descriptor = self.get_dummy_course(start='2012-10-15T12:00')
+        descriptor = get_dummy_course(start='2012-10-15T12:00')
         assert(descriptor.is_newish is False)
 
-        descriptor = self.get_dummy_course(start='2012-12-31T12:00')
+        descriptor = get_dummy_course(start='2012-12-31T12:00')
         assert(descriptor.is_newish is True)
 
     def test_end_date_text(self):
         # No end date set, returns empty string.
-        d = self.get_dummy_course('2012-12-02T12:00')
+        d = get_dummy_course('2012-12-02T12:00')
         self.assertEqual('', d.end_date_text)
 
-        d = self.get_dummy_course('2012-12-02T12:00', end='2014-9-04T12:00')
+        d = get_dummy_course('2012-12-02T12:00', end='2014-9-04T12:00')
         self.assertEqual('Sep 04, 2014', d.end_date_text)
 
+
+class DiscussionTopicsTestCase(unittest.TestCase):
     def test_default_discussion_topics(self):
-        d = self.get_dummy_course('2012-12-02T12:00')
+        d = get_dummy_course('2012-12-02T12:00')
         self.assertEqual({'General': {'id': 'i4x-test_org-test_course-course-test'}}, d.discussion_topics)