Deduplicate course runs in typeahead by course

ECOM-7338

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

@@ -473,6 +473,26 @@ class TypeaheadSearchViewTests(DefaultPartnerMixin, TypeaheadSerializationMixin,
         self.assertEqual(len(response_data['course_runs']), RESULT_COUNT)
         self.assertEqual(len(response_data['programs']), RESULT_COUNT)
 
+    def test_typeahead_deduplicate_course_runs(self):
+        """ Verify the typeahead response will only include the first course run per course. """
+        RESULT_COUNT = TypeaheadSearchView.RESULT_COUNT
+        title = "Test"
+        course1 = CourseFactory(partner=self.partner)
+        course2 = CourseFactory(partner=self.partner)
+        for i in range(RESULT_COUNT):
+            CourseRunFactory(title="{}{}{}".format(title, course1.title, i), course=course1)
+        for i in range(RESULT_COUNT):
+            CourseRunFactory(title="{}{}{}".format(title, course2.title, i), course=course2)
+        response = self.get_response({'q': title})
+        assert response.status_code == 200
+        response_data = response.json()
+
+        # There are many runs for both courses, but only one from each will be included
+        course_runs = response_data['course_runs']
+        assert len(course_runs) == 2
+        # compare course titles embedded in course run title to ensure that course runs belong to different courses
+        assert course_runs[0]['title'][4:-1] != course_runs[1]['title'][4:-1]
+
     def test_typeahead_multiple_authoring_organizations(self):
         """ Test typeahead response with multiple authoring organizations. """
         title = "Design"

course_discovery/apps/api/v1/views/search.py

@@ -134,7 +134,17 @@ class TypeaheadSearchView(PartnerMixin, APIView):
             SQ(authoring_organizations_autocomplete=clean_query)
         )
         course_runs = course_runs.filter(published=True).exclude(hidden=True).filter(partner=partner.short_code)
-        course_runs = course_runs[:self.RESULT_COUNT]
+
+        # Get first three results after deduplicating by course run
+        course_runs_list, course_keys_set = [], set()
+        for course_run in course_runs:
+            course_key = course_run.course_key
+            if course_key in course_keys_set:
+                continue
+            course_keys_set.add(course_key)
+            course_runs_list.append(course_run)
+            if len(course_runs_list) == 3:
+                break
 
         programs = sqs.models(Program).filter(
             SQ(title_autocomplete=clean_query) |
@@ -143,7 +153,7 @@ class TypeaheadSearchView(PartnerMixin, APIView):
         programs = programs.filter(status=ProgramStatus.Active).filter(partner=partner.short_code)
         programs = programs[:self.RESULT_COUNT]
 
-        return course_runs, programs
+        return course_runs_list, programs
 
     def get(self, request, *args, **kwargs):
         """