fixed cohort test by using hasattr instead of .get()

analytics_data_api/v0/serializers.py

@@ -1,10 +1,13 @@
+from collections import OrderedDict
 from urlparse import urljoin
 from django.conf import settings
 from rest_framework import pagination, serializers
+from rest_framework.response import Response
 
 from analytics_data_api.constants import (
     engagement_events,
     enrollment_modes,
+    learner,
 )
 from analytics_data_api.v0 import models
 
@@ -344,7 +347,7 @@ class LearnerSerializer(serializers.Serializer):
     segments = serializers.SerializerMethodField()
     engagements = serializers.SerializerMethodField()
     enrollment_date = serializers.DateTimeField(format=settings.DATE_FORMAT)
-    cohort = serializers.CharField()
+    cohort = serializers.SerializerMethodField()
 
     def get_segments(self, obj):
         # using hasattr() instead because DocType.get() is overloaded and makes a request
@@ -355,7 +358,11 @@ def get_segments(self, obj):
             return []
 
     def get_cohort(self, obj):
-        return obj.get('cohort', None)
+        if hasattr(obj, 'cohort') and len(obj.cohort) > 0:
+            # json parsing will fail unless in unicode
+            return obj.cohort
+        else:
+            return None
 
     def get_account_url(self, obj):
         if settings.LMS_USER_ACCOUNT_BASE_URL:
@@ -388,20 +395,21 @@ class EdxPaginationSerializer(pagination.PageNumberPagination):
     """
     Adds values to the response according to edX REST API Conventions.
     """
-    num_pages = serializers.ReadOnlyField(source='paginator.num_pages')
-
-
-class ElasticsearchDSLSearchSerializer(EdxPaginationSerializer):
-    def __init__(self, *args, **kwargs):
-        """Make sure that the elasticsearch query is executed."""
-        # Because the elasticsearch-dsl search object has a different
-        # API from the queryset object that's expected by the django
-        # Paginator object, we have to manually execute the query.
-        # Note that the `kwargs['instance']` is the Page object, and
-        # `kwargs['instance'].object_list` is actually an
-        # elasticsearch-dsl search object.
-        kwargs['instance'].object_list = kwargs['instance'].object_list.execute()
-        super(ElasticsearchDSLSearchSerializer, self).__init__(*args, **kwargs)
+    page_size_query_param = 'page_size'
+    page_size = learner.LEARNER_API_DEFAULT_LIST_PAGE_SIZE
+    max_page_size = 100  # TODO -- tweak during load testing
+
+    def get_paginated_response(self, data):
+        # The output is more readable with num_pages included not at the end, but
+        # inefficient to insert into an OrderedDict, so the response is copied from
+        # rest_framework.pagination with the addition of "num_pages".
+        return Response(OrderedDict([
+            ('count', self.page.paginator.count),
+            ('num_pages', self.page.paginator.num_pages),
+            ('next', self.get_next_link()),
+            ('previous', self.get_previous_link()),
+            ('results', data)
+        ]))
 
 
 # pylint: disable=abstract-method

analytics_data_api/v0/tests/views/test_learners.py

@@ -205,7 +205,7 @@ def assert_learners_returned(self, response, expected_learners):
         returned.
         """
         self.assertEqual(response.status_code, 200)
-        returned_learners = json.loads(response.content)
+        returned_learners = json.loads(response.content)['results']
         if expected_learners is None:
             self.assertEqual(returned_learners, list())
         else:

analytics_data_api/v0/views/learners.py

@@ -5,9 +5,6 @@
 
 from rest_framework import generics, status
 
-from analytics_data_api.constants import (
-    learner
-)
 from analytics_data_api.v0.exceptions import (
     LearnerEngagementTimelineNotFoundError,
     LearnerNotFoundError,
@@ -21,7 +18,7 @@
 )
 from analytics_data_api.v0.serializers import (
     CourseLearnerMetadataSerializer,
-    ElasticsearchDSLSearchSerializer,
+    EdxPaginationSerializer,
     EngagementDaySerializer,
     LastUpdatedSerializer,
     LearnerSerializer,
@@ -187,9 +184,7 @@ class LearnerListView(LastUpdateMixin, CourseViewMixin, generics.ListAPIView):
 
     """
     serializer_class = LearnerSerializer
-    pagination_serializer_class = ElasticsearchDSLSearchSerializer
-    paginate_by_param = 'page_size'
-    paginate_by = learner.LEARNER_API_DEFAULT_LIST_PAGE_SIZE
+    pagination_class = EdxPaginationSerializer
     max_paginate_by = 100  # TODO -- tweak during load testing
 
     def _validate_query_params(self):
@@ -222,8 +217,9 @@ def list(self, request, *args, **kwargs):
         """
         response = super(LearnerListView, self).list(request, args, kwargs)
         last_updated = self.get_last_updated()
-        for result in response.data:
-            result.update(last_updated)
+        if response.data['results'] is not None:
+            for result in response.data['results']:
+                result.update(last_updated)
         return response
 
     def get_queryset(self):