diff --git a/nova/tests/unit/virt/libvirt/test_firewall.py b/nova/tests/unit/virt/libvirt/test_firewall.py
index 8b727865bd84..be4e9b39123f 100644
--- a/nova/tests/unit/virt/libvirt/test_firewall.py
+++ b/nova/tests/unit/virt/libvirt/test_firewall.py
@@ -149,9 +149,10 @@ class IptablesFirewallTestCase(test.NoDBTestCase):
         inst.info_cache.deleted = False
         return inst
 
+    @mock.patch.object(linux_net.iptables_manager, "execute")
     @mock.patch.object(objects.InstanceList, "get_by_security_group_id")
     @mock.patch.object(objects.SecurityGroupRuleList, "get_by_instance")
-    def test_static_filters(self, mock_secrule, mock_instlist):
+    def test_static_filters(self, mock_secrule, mock_instlist, fake_execute):
         UUID = "2674993b-6adb-4733-abd9-a7c10cc1f146"
         SRC_UUID = "0e0a76b2-7c52-4bc0-9a60-d83017e42c1a"
         instance_ref = self._create_instance_ref(UUID)
@@ -247,7 +248,7 @@ class IptablesFirewallTestCase(test.NoDBTestCase):
 
         network_model = _fake_network_info(self, 1)
 
-        linux_net.iptables_manager.execute = fake_iptables_execute
+        fake_execute.side_effect = fake_iptables_execute
 
         self.stub_out('nova.objects.Instance.get_network_info',
                       lambda instance: network_model)