diff --git a/nova/tests/compute/test_compute_utils.py b/nova/tests/compute/test_compute_utils.py
index 144ac9f00c7c..83ed90ef0757 100644
--- a/nova/tests/compute/test_compute_utils.py
+++ b/nova/tests/compute/test_compute_utils.py
@@ -215,6 +215,7 @@ class UsageInfoTestCase(test.TestCase):
         self.stubs.Set(network_api.API, 'get_instance_nw_info',
                        fake_get_nw_info)
 
+        notifier_api._reset_drivers()
         self.flags(use_local=True, group='conductor')
         self.flags(compute_driver='nova.virt.fake.FakeDriver',
                    notification_driver=[test_notifier.__name__],
diff --git a/nova/tests/test_notifications.py b/nova/tests/test_notifications.py
index 0677b10f8e41..7374a72cd3b7 100644
--- a/nova/tests/test_notifications.py
+++ b/nova/tests/test_notifications.py
@@ -54,6 +54,7 @@ class NotificationsTestCase(test.TestCase):
                 fake_get_nw_info)
         fake_network.set_stub_network_methods(self.stubs)
 
+        notifier_api._reset_drivers()
         self.flags(compute_driver='nova.virt.fake.FakeDriver',
                    notification_driver=[test_notifier.__name__],
                    network_manager='nova.network.manager.FlatManager',