Improve test to ensure that post_delete was actually called

        models.signals.post_delete.disconnect(log_pre_delete)

    def test_relational_post_delete_signals_happen_before_parent_object(self):

        deletions = []

        def log_post_delete(instance, **kwargs):

            self.assertTrue(R.objects.filter(pk=instance.r_id))

            self.assertEquals(type(instance), S)

            deletions.append(instance.id)

        r = R.objects.create(pk=1)

        S.objects.create(pk=1, r=r)

        finally:

            models.signals.post_delete.disconnect(log_post_delete)

        self.assertEquals(len(deletions), 1)

        self.assertEquals(deletions[0], 1)

    @skipUnlessDBFeature("can_defer_constraint_checks")

    def test_can_defer_constraint_checks(self):

        u = User.objects.create(