diff --git a/nova/tests/test_volume.py b/nova/tests/test_volume.py
index aef0b57f..57ca5278 100644
--- a/nova/tests/test_volume.py
+++ b/nova/tests/test_volume.py
@@ -30,6 +30,7 @@ from nova import exception
 from nova import flags
 from nova.openstack.common import importutils
 from nova.openstack.common import log as logging
+from nova.openstack.common.notifier import api as notifier_api
 from nova.openstack.common.notifier import test_notifier
 from nova.openstack.common import rpc
 import nova.policy
@@ -50,7 +51,7 @@ class VolumeTestCase(test.TestCase):
         self.compute = importutils.import_object(FLAGS.compute_manager)
         self.flags(compute_driver='nova.virt.fake.FakeDriver')
         self.stubs.Set(nova.flags.FLAGS, 'notification_driver',
-                'nova.openstack.common.notifier.test_notifier')
+                ['nova.openstack.common.notifier.test_notifier'])
         self.volume = importutils.import_object(FLAGS.volume_manager)
         self.context = context.get_admin_context()
         instance = db.instance_create(self.context, {})
@@ -60,6 +61,7 @@ class VolumeTestCase(test.TestCase):
 
     def tearDown(self):
         db.instance_destroy(self.context, self.instance_uuid)
+        notifier_api._reset_drivers()
         super(VolumeTestCase, self).tearDown()
 
     @staticmethod
diff --git a/nova/tests/test_volume_utils.py b/nova/tests/test_volume_utils.py
index 8d0caab2..cd81e67f 100644
--- a/nova/tests/test_volume_utils.py
+++ b/nova/tests/test_volume_utils.py
@@ -22,6 +22,7 @@ from nova import db
 from nova import flags
 from nova.openstack.common import importutils
 from nova.openstack.common import log as logging
+from nova.openstack.common.notifier import api as notifier_api
 from nova.openstack.common.notifier import test_notifier
 from nova import test
 from nova.volume import utils as volume_utils
@@ -39,7 +40,7 @@ class UsageInfoTestCase(test.TestCase):
                    stub_network=True,
                    host='fake')
         self.stubs.Set(flags.FLAGS, 'notification_driver',
-                'nova.openstack.common.notifier.test_notifier')
+                ['nova.openstack.common.notifier.test_notifier'])
         self.volume = importutils.import_object(FLAGS.volume_manager)
         self.user_id = 'fake'
         self.project_id = 'fake'
@@ -48,6 +49,10 @@ class UsageInfoTestCase(test.TestCase):
         self.context = context.RequestContext(self.user_id, self.project_id)
         test_notifier.NOTIFICATIONS = []
 
+    def tearDown(self):
+        notifier_api._reset_drivers()
+        super(UsageInfoTestCase, self).tearDown()
+
     def _create_volume(self, params={}):
         """Create a test volume"""
         vol = {}