diff --git a/heat/engine/clients/os/nova.py b/heat/engine/clients/os/nova.py
index cd19b2ea50..c0f280bbf8 100644
--- a/heat/engine/clients/os/nova.py
+++ b/heat/engine/clients/os/nova.py
@@ -793,7 +793,7 @@ echo -e '%s\tALL=(ALL)\tNOPASSWD: ALL' >> /etc/sudoers
             server = self.fetch_server(server_id)
             if server:
                 server.interface_detach(port_id)
-                return True
+        return True
 
     def interface_attach(self, server_id, port_id=None, net_id=None, fip=None,
                          security_groups=None):
diff --git a/heat/tests/openstack/nova/test_server.py b/heat/tests/openstack/nova/test_server.py
index f4aec2a815..47ab989634 100644
--- a/heat/tests/openstack/nova/test_server.py
+++ b/heat/tests/openstack/nova/test_server.py
@@ -5073,7 +5073,7 @@ class ServerInternalPortTest(ServersTest):
         server.client().servers.get.return_value = nova_server
 
         server.prepare_for_replace()
-        check_detach.assert_not_called()
+        self.assertEqual(3, check_detach.call_count)
         self.assertEqual(0, self.port_delete.call_count)
 
     def test_prepare_ports_for_replace_error_state(self):