Use set comprehension instead of list comprehension when collecting Course model primary keys.

This is an attempt to fix an issue we are seeing with unreliable search results.

ENT-444

course_discovery/apps/api/v1/tests/test_views/test_affiliate_window.py

@@ -46,7 +46,7 @@ class AffiliateWindowViewSetTests(ElasticsearchTestMixin, SerializationMixin, AP
 
     def test_affiliate_with_supported_seats(self):
         """ Verify that endpoint returns course runs for verified and professional seats only. """
-        with self.assertNumQueries(7):
+        with self.assertNumQueries(8):
             response = self.client.get(self.affiliate_url)
 
         self.assertEqual(response.status_code, 200)

course_discovery/apps/course_metadata/migrations/0056_auto_20170620_1351.py

+# -*- coding: utf-8 -*-
+# Generated by Django 1.10.7 on 2017-06-20 13:51
+from __future__ import unicode_literals
+
+from django.db import migrations
+
+
+def create_switch(apps, schema_editor):
+    """Create the log_course_search_queries switch if it does not already exist."""
+    Switch = apps.get_model('waffle', 'Switch')
+    Switch.objects.get_or_create(name='log_course_search_queries', defaults={'active': False})
+
+
+def delete_switch(apps, schema_editor):
+    """Delete the log_course_search_queries switch."""
+    Switch = apps.get_model('waffle', 'Switch')
+    Switch.objects.filter(name='log_course_search_queries').delete()
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('course_metadata', '0055_program_hidden'),
+        ('waffle', '0001_initial'),
+    ]
+
+    operations = [
+        migrations.RunPython(create_switch, delete_switch),
+    ]

course_discovery/apps/course_metadata/models.py

@@ -334,7 +334,14 @@ class Course(TimeStampedModel):
         """
         query = clean_query(query)
         results = SearchQuerySet().models(cls).raw_search(query)
-        ids = [result.pk for result in results]
+        ids = {result.pk for result in results}
+
+        if waffle.switch_is_active('log_course_search_queries'):
+            logger.info('Course search query {query} returned the following ids: {course_ids}'.format(
+                query=query,
+                course_ids=ids
+            ))
+
         return cls.objects.filter(pk__in=ids)
 
 

course_discovery/apps/course_metadata/tests/test_models.py

@@ -44,6 +44,7 @@ class CourseTests(ElasticsearchTestMixin, TestCase):
 
     def test_search(self):
         """ Verify the method returns a filtered queryset of courses. """
+        toggle_switch('log_course_search_queries', active=True)
         title = 'Some random title'
         courses = factories.CourseFactory.create_batch(3, title=title)
         # Sort lowercase keys to prevent different sort orders due to casing.