Performance and test improvement for LearnerMetricsViewSet

figures/serializers.py

@@ -798,7 +798,7 @@ class EnrollmentMetricsSerializerV2(serializers.ModelSerializer):
     course_id = serializers.CharField()
     date_enrolled = serializers.DateTimeField(source='created',
                                               format="%Y-%m-%d")
-    is_enrolled = serializers.BooleanField()
+    is_enrolled = serializers.BooleanField(source='is_active')
     progress_percent = serializers.SerializerMethodField()
     progress_details = serializers.SerializerMethodField()
 
@@ -821,14 +821,6 @@ def to_representation(self, instance):
             user=instance.user, course_id=str(instance.course_id))
         return super(EnrollmentMetricsSerializerV2, self).to_representation(instance)
 
-    def get_is_enrolled(self, obj):
-        """
-        CourseEnrollment has to do some work to get this value
-        TODO: inspect CourseEnrollment._get_enrollment_state to see how we
-        can speed this up, avoiding construction of `CourseEnrollmentState`
-        """
-        return CourseEnrollment.is_enrolled(obj.user, obj.course_id)
-
     def get_progress_percent(self, obj):  # pylint: disable=unused-argument
         value = self._lcgm.progress_percent if self._lcgm else 0
         return float(Decimal(value).quantize(Decimal('.00')))
@@ -866,7 +858,7 @@ class LearnerMetricsSerializer(serializers.ModelSerializer):
 
     class Meta:
         model = get_user_model()
-        # list_serializer_class = LearnerMetricsListSerializer
+        list_serializer_class = LearnerMetricsListSerializer
         fields = ('id', 'username', 'email', 'fullname', 'is_active',
                   'date_joined', 'enrollments')
         read_only_fields = fields
@@ -876,14 +868,14 @@ def get_enrollments(self, user):
         Rely on the caller (the view) to filter users and prefetch related
         """
 
-        user_enrollments = user.courseenrollment_set.all()
+        # user_enrollments = user.courseenrollment_set.all()
 
         # Still in testing, and remarked out to get the first pass PR through:
         # This is where the ListSerializer helps, by doing the database hit in
         # one set of queries at the top, then using the results for each. But
         # it still needs work
 
-        # user_enrollments = user.courseenrollment_set.filter(
-        #     course_id__in=self.parent.course_keys)
+        user_enrollments = user.courseenrollment_set.filter(
+            course_id__in=self.parent.course_keys)
 
         return EnrollmentMetricsSerializerV2(user_enrollments, many=True).data

tests/views/test_learner_metrics_viewset.py

@@ -81,6 +81,16 @@ def make_request(self, monkeypatch, request_path, site, caller, action):
         view = self.view_class.as_view({'get': action})
         return view(request)
 
+    def matching_enrollment_set_to_course_ids(self, enrollments, course_ids):
+        """
+        enrollment course ids need to be a subset of course_ids
+        It is ok if there are none or fewer enrollments than course_ids because
+        a learner might not be enrolled in all the courses on which we are
+        filtering
+        """
+        enroll_course_ids = set([rec['course_id'] for rec in enrollments])
+        return enroll_course_ids.issubset(set([str(rec) for rec in course_ids]))
+
     def test_list_method_all(self, monkeypatch, lm_test_data):
         """Partial test coverage to check we get all site users
 
@@ -150,6 +160,10 @@ def test_course_param_single(self, monkeypatch, lm_test_data):
         expected_user_ids = [obj.user.id for obj in course_enrollments]
         assert set(result_ids) == set(expected_user_ids)
 
+        for rec in results:
+            assert self.matching_enrollment_set_to_course_ids(
+                rec['enrollments'], [our_courses[0].id])
+
     def test_course_param_multiple(self, monkeypatch, lm_test_data):
         """Test that the 'course' query parameter works
 
@@ -185,8 +199,14 @@ def test_course_param_multiple(self, monkeypatch, lm_test_data):
                                                   courses=filtered_courses)
         expected_user_ids = [obj.user.id for obj in expected_enrollments]
         assert set(result_ids) == set(expected_user_ids)
+        for rec in results:
+            assert self.matching_enrollment_set_to_course_ids(
+                rec['enrollments'], [rec.id for rec in filtered_courses])
 
     def invalid_course_ids_raise_404(self, monkeypatch, lm_test_data, query_params):
+        """
+        Helper method to test expected 404 calls
+        """
         us = lm_test_data['us']
         them = lm_test_data['them']