diff --git a/cinder/tests/unit/backup/drivers/test_backup_google.py b/cinder/tests/unit/backup/drivers/test_backup_google.py
index e39369d6719..61e9fd51817 100644
--- a/cinder/tests/unit/backup/drivers/test_backup_google.py
+++ b/cinder/tests/unit/backup/drivers/test_backup_google.py
@@ -177,6 +177,12 @@ class GoogleBackupDriverTestCase(test.TestCase):
         for _i in range(0, 64):
             self.volume_file.write(os.urandom(units.Ki))
             self.size_volume_file += 1024
+        # Note(yikun): It mocks out the backup notifier to avoid to leak
+        # notifications into other test.
+        notify_patcher = mock.patch(
+            'cinder.volume.utils.notify_about_backup_usage')
+        notify_patcher.start()
+        self.addCleanup(notify_patcher.stop)
 
     @gcs_client
     def test_backup(self):
diff --git a/cinder/tests/unit/backup/drivers/test_backup_nfs.py b/cinder/tests/unit/backup/drivers/test_backup_nfs.py
index c65d0131fcc..eeafc9809ce 100644
--- a/cinder/tests/unit/backup/drivers/test_backup_nfs.py
+++ b/cinder/tests/unit/backup/drivers/test_backup_nfs.py
@@ -67,6 +67,12 @@ class BackupNFSShareTestCase(test.TestCase):
         super(BackupNFSShareTestCase, self).setUp()
         self.ctxt = context.get_admin_context()
         self.mock_object(nfs, 'LOG')
+        # Note(yikun): It mocks out the backup notifier to avoid to leak
+        # notifications into other test.
+        notify_patcher = mock.patch(
+            'cinder.volume.utils.notify_about_backup_usage')
+        notify_patcher.start()
+        self.addCleanup(notify_patcher.stop)
 
     def test_check_configuration_no_backup_share(self):
         self.override_config('backup_share', None)