Tested that get_or_create raises IntegrityError.

It used to raise "DatabaseError: no such savepoint" with the old
transaction management. Closes #15117.

tests/get_or_create/models.py

@@ -24,3 +24,7 @@ class Person(models.Model):
 class ManualPrimaryKeyTest(models.Model):
     id = models.IntegerField(primary_key=True)
     data = models.CharField(max_length=100)
+
+
+class Profile(models.Model):
+    person = models.ForeignKey(Person, primary_key=True)

tests/get_or_create/tests.py

@@ -4,9 +4,9 @@ from datetime import date
 import traceback
 
 from django.db import IntegrityError
-from django.test import TestCase
+from django.test import TestCase, TransactionTestCase
 
-from .models import Person, ManualPrimaryKeyTest
+from .models import Person, ManualPrimaryKeyTest, Profile
 
 
 class GetOrCreateTests(TestCase):
@@ -64,3 +64,16 @@ class GetOrCreateTests(TestCase):
             formatted_traceback = traceback.format_exc()
             self.assertIn('obj.save', formatted_traceback)
 
+
+class GetOrCreateTransactionTests(TransactionTestCase):
+
+    def test_get_or_create_integrityerror(self):
+        # Regression test for #15117. Requires a TransactionTestCase on
+        # databases that delay integrity checks until the end of transactions,
+        # otherwise the exception is never raised.
+        try:
+            Profile.objects.get_or_create(person=Person(id=1))
+        except IntegrityError:
+            pass
+        else:
+            self.skipTest("This backend does not support integrity checks.")