Fix backfill_enrollment_data_for_course task

* Problem was that `update_enrollment_data_for_course` returns a list of
tuples. Each tuple is `(object, created)`, where `object` is the
EnrollmentData record and `created` tells if the record was created
* Added logging to the backfill task
* Updated tests

figures/tasks.py

@@ -326,13 +326,20 @@ def populate_daily_metrics_next(site_id=None, force_update=False):
 def backfill_enrollment_data_for_course(course_id):
     """Create or update EnrollmentData records for the course
 
-    Simple wrapper to run the enrollment update as a Celery task
+    This is a simple wrapper to run the enrollment update as a Celery task
 
     We usually run this task through the Figures Django management command,
     `backfill_figures_enrollment_data`
     """
-    ed_objects = update_enrollment_data_for_course(course_id)
-    return [obj.id for obj in ed_objects]
+    # results are a list of (object, created_flag) tuples
+    updated = update_enrollment_data_for_course(course_id)
+    # Do we want to log this?
+    # ids = [obj.id for obj, _ in ed_objects]
+    # Since this is a Celery task, don't return a value
+    msg = ('figures.tasks.backfill_enrollment_data_for_course "{course_id}".'
+           ' Updated {edrec_count} enrollment data records.')
+
+    logger.info(msg.format(course_id=course_id, edrec_count=len(updated)))
 
 
 #

tests/tasks/test_backfill_tasks.py

@@ -1,20 +1,55 @@
 """Test Figures backfill Celery tasks
 """
 from __future__ import absolute_import
+import logging
+import pytest
 
 from figures.tasks import backfill_enrollment_data_for_course
 
 from tests.factories import EnrollmentDataFactory
 
 
-def test_backfill_enrollment_data_for_course(transactional_db, monkeypatch):
-    """
-    The Celery task is a simple wrapper around the pipeline function
-    """
-    course_id = 'course-v1:SomeOrg+SomeNum+SomeRun'
-    ed_recs = [EnrollmentDataFactory() for _ in range(2)]
+@pytest.mark.django_db
+class TestBackfillEnrollmentDataForCourse(object):
 
-    func_path = 'figures.tasks.update_enrollment_data_for_course'
-    monkeypatch.setattr(func_path, lambda course_id: ed_recs)
-    ed_ids = backfill_enrollment_data_for_course(course_id)
-    assert set(ed_ids) == set([obj.id for obj in ed_recs])
+    @pytest.fixture(autouse=True)
+    def setup(self, db):
+        self.expected_message_template = (
+            'figures.tasks.backfill_enrollment_data_for_course "{course_id}".'
+            ' Updated {edrec_count} enrollment data records.')
+
+    def test_backfill_enrollment_data_for_course_no_update(self, transactional_db,
+                                                           monkeypatch, caplog):
+        """
+        The Celery task is a simple wrapper around the pipeline function
+        """
+        course_id = 'course-v1:SomeOrg+SomeNum+SomeRun'
+
+        # The function returns a list of tuples with (object, created)
+        # ed_recs = [(EnrollmentDataFactory(), False) for _ in range(2)]
+        caplog.set_level(logging.INFO)
+        func_path = 'figures.tasks.update_enrollment_data_for_course'
+        monkeypatch.setattr(func_path, lambda course_id: [])
+        backfill_enrollment_data_for_course(course_id)
+        assert len(caplog.records) == 1
+        assert caplog.records[0].message == self.expected_message_template.format(
+            course_id=course_id,
+            edrec_count=0)
+
+    def test_backfill_enrollment_data_for_course_with_updates(self, transactional_db,
+                                                              monkeypatch, caplog):
+        """
+        The Celery task is a simple wrapper around the pipeline function
+        """
+        course_id = 'course-v1:SomeOrg+SomeNum+SomeRun'
+
+        # The function returns a list of tuples with (object, created)
+        ed_recs = [(EnrollmentDataFactory(), False) for _ in range(2)]
+        caplog.set_level(logging.INFO)
+        func_path = 'figures.tasks.update_enrollment_data_for_course'
+        monkeypatch.setattr(func_path, lambda course_id: ed_recs)
+        backfill_enrollment_data_for_course(course_id)
+        assert len(caplog.records) == 1
+        assert caplog.records[0].message == self.expected_message_template.format(
+            course_id=course_id,
+            edrec_count=len(ed_recs))