fix: bulk create on mysql

edx_exams/apps/api/v1/views.py

@@ -873,12 +873,7 @@ def post(self, request, course_id):
                     data={'detail': 'Exam does not exist'}
                 )
 
-            StudentAllowance.objects.bulk_create(
-                allowance_objects,
-                update_conflicts=True,
-                unique_fields=['user', 'exam'],
-                update_fields=['extra_time_mins']
-            )
+            StudentAllowance.bulk_create_or_update(allowance_objects)
 
             return Response(status=status.HTTP_200_OK)
         else:

edx_exams/apps/core/models.py

@@ -4,7 +4,7 @@
 
 from django.contrib.auth.models import AbstractUser
 from django.core.exceptions import ObjectDoesNotExist
-from django.db import models, transaction
+from django.db import connection, models, transaction
 from django.db.models import Q
 from django.utils.translation import gettext_lazy as _
 from model_utils.models import TimeStampedModel
@@ -454,6 +454,26 @@ class Meta:
         verbose_name = 'student allowance'
         unique_together = ('user', 'exam')
 
+    @classmethod
+    def bulk_create_or_update(cls, allowances):
+        """
+        Create or update multiple allowances.
+
+        SQLite and Postgres have an additional requirement for bulk_create
+        when using update_conflicts=True. This app expects to run on MySQL
+        however our tests run on SQLite where 'unique_fields' is needed.
+        """
+        unique_fields = None
+        if connection.features.supports_update_conflicts_with_target:
+            unique_fields = ['user', 'exam']
+
+        cls.objects.bulk_create(
+            allowances,
+            update_conflicts=True,
+            unique_fields=unique_fields,
+            update_fields=['extra_time_mins'],
+        )
+
     @classmethod
     def get_allowances_for_course(cls, course_id):
         """

edx_exams/apps/core/tests/test_models.py

@@ -148,6 +148,24 @@ def setUp(self):
         self.course_id = 'course-v1:edX+Test+Test_Course'
         self.exam = ExamFactory(course_id=self.course_id)
 
+    def test_bulk_create_or_update(self):
+        """
+        Test bulk_create_or_update can create new allowances and update existing ones.
+        """
+        conflict_user = UserFactory()
+        conflict_allowance = StudentAllowanceFactory(user=conflict_user, exam=self.exam, extra_time_mins=66)
+        allowances = [
+            StudentAllowance(user=conflict_user, exam=self.exam, extra_time_mins=19),
+            StudentAllowance(user=UserFactory(), exam=self.exam, extra_time_mins=29),
+            StudentAllowance(user=UserFactory(), exam=self.exam, extra_time_mins=39),
+        ]
+
+        self.assertEqual(StudentAllowance.objects.count(), 1)
+        StudentAllowance.bulk_create_or_update(allowances)
+        self.assertEqual(StudentAllowance.objects.count(), 3)
+        conflict_allowance.refresh_from_db()
+        self.assertEqual(conflict_allowance.extra_time_mins, 19)
+
     def test_get_allowance_for_user(self):
         user = UserFactory()
         user_2 = UserFactory()