Switch several assertNumQueries to use the context manager, which is much more beautiful.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@16986 bcc190cf-cafb-0310-a4f2-bffc1f526a37

tests/regressiontests/forms/tests/models.py

@@ -1,5 +1,5 @@
 # -*- coding: utf-8 -*-
-from __future__ import absolute_import
+from __future__ import with_statement, absolute_import
 
 import datetime
 
@@ -28,11 +28,10 @@ class TestTicket12510(TestCase):
         self.groups = [Group.objects.create(name=name) for name in 'abc']
 
     def test_choices_not_fetched_when_not_rendering(self):
-        def test():
+        # only one query is required to pull the model from DB
+        with self.assertNumQueries(1):
             field = ModelChoiceField(Group.objects.order_by('-name'))
             self.assertEqual('a', field.clean(self.groups[0].pk).name)
-        # only one query is required to pull the model from DB
-        self.assertNumQueries(1, test)
 
 class ModelFormCallableModelDefault(TestCase):
     def test_no_empty_option(self):