diff --git a/ovn_octavia_provider/tests/functional/test_driver.py b/ovn_octavia_provider/tests/functional/test_driver.py
index e569f762..41ee7603 100644
--- a/ovn_octavia_provider/tests/functional/test_driver.py
+++ b/ovn_octavia_provider/tests/functional/test_driver.py
@@ -213,10 +213,10 @@ class TestOctaviaOvnProviderDriver(
                     self.assertEqual(expected_lb, observed_lb)
                     found = True
             if not found:
-                raise Exception("Expected LB %(name)s for protocol %(proto)s "
-                                "not found in observed_lbs", {
-                                    'name': expected_lb.get('name'),
-                                    'proto': expected_lb.get('proto')})
+                raise Exception("Expected LB %s for protocol %s "
+                                "not found in observed_lbs" % (
+                                    expected_lb.get('name'),
+                                    expected_lb.get('proto')))
 
     def _is_lb_associated_to_ls(self, lb_name, ls_name):
         return self._is_lb_associated_to_tab(