address comments

analytics_data_api/v0/models.py

@@ -223,7 +223,7 @@ class RosterEntry(DocType):
     email = String()
     enrollment_mode = String()
     cohort = String()
-    segments = String(fields={'raw': String()})
+    segments = String()  # segments is an array/list of strings
     problems_attempted = Integer()
     problems_completed = Integer()
     problem_attempts_per_completed = Float()

analytics_data_api/v0/serializers.py

@@ -348,8 +348,7 @@ class LearnerSerializer(serializers.Serializer, DefaultIfNoneMixin):
             engagements[field] = self.default_if_none(getattr(obj, field, None), 0)
 
         # preserve null values for problem attempts per completed
-        no_default_field = 'problem_attempts_per_completed'
-        engagements[no_default_field] = getattr(obj, no_default_field, None)
+        engagements['problem_attempts_per_completed'] = getattr(obj, 'problem_attempts_per_completed', None)
 
         return engagements
 

analytics_data_api/v0/tests/views/test_learners.py

@@ -150,13 +150,13 @@ class LearnerTests(VerifyCourseIdMixin, LearnerAPITestMixin, TestCaseWithAuthent
     @ddt.data(
         ('ed_xavier', 'Edward Xavier', 'edX/DemoX/Demo_Course', 'honor', ['has_potential'], 'Team edX',
          43, 3, 6, 0, 8.4, 2, '2015-04-24', '2015-08-05'),
-        ('ed_xavier', 'Edward Xavier', 'edX/DemoX/Demo_Course', 'verified', None, None,
-         None, None, None, None, None, None, None, None),
+        ('ed_xavier', 'Edward Xavier', 'edX/DemoX/Demo_Course', 'verified'),
     )
     @ddt.unpack
-    def test_get_user(self, username, name, course_id, enrollment_mode, segments, cohort, problems_attempted,
-                      problems_completed, videos_viewed, discussions_contributed, problem_attempts_per_completed,
-                      attempt_ratio_order, enrollment_date, last_updated):
+    def test_get_user(self, username, name, course_id, enrollment_mode, segments=None, cohort=None,
+                      problems_attempted=None, problems_completed=None, videos_viewed=None,
+                      discussions_contributed=None, problem_attempts_per_completed=None,
+                      attempt_ratio_order=None, enrollment_date=None, last_updated=None):
 
         self.create_learners([{
             "username": username,

analytics_data_api/v0/views/learners.py

@@ -176,9 +176,8 @@ class LearnerListView(CourseViewMixin, generics.ListAPIView):
         query_params = self.request.QUERY_PARAMS
 
         # Ordering by problem_attempts_per_completed can be ambiguous because
-        # it's a ratio values could be infinite (e.g. divide by zero) if no problems
-        # were completed.  Instead, sorting by attempt_ratio_order will produce
-        # a sensible ordering
+        # values could be infinite (e.g. divide by zero) if no problems were completed.
+        # Instead, sorting by attempt_ratio_order will produce a sensible ordering
         order_by = query_params.get('order_by')
         order_by = 'attempt_ratio_order' if order_by == 'problem_attempts_per_completed' else order_by