Removed unnecessary transaction wrapping in expressions test.

tests/expressions/tests.py

@@ -5,7 +5,7 @@ import uuid
 from copy import deepcopy
 
 from django.core.exceptions import FieldError
-from django.db import DatabaseError, connection, models, transaction
+from django.db import DatabaseError, connection, models
 from django.db.models import CharField, Q, TimeField, UUIDField
 from django.db.models.aggregates import (
     Avg, Count, Max, Min, StdDev, Sum, Variance,
@@ -237,7 +237,6 @@ class BasicExpressionsTests(TestCase):
             "foo",
         )
 
-        with transaction.atomic():
         msg = "Joined field references are not permitted in this query"
         with self.assertRaisesMessage(FieldError, msg):
             Company.objects.exclude(