Fix assertions
diff --git a/cvp_checks/tests/test_services.py b/cvp_checks/tests/test_services.py
index 284956d..a623508 100644
--- a/cvp_checks/tests/test_services.py
+++ b/cvp_checks/tests/test_services.py
@@ -32,5 +32,5 @@
             row.insert(0, srv)
             pkts_data.append(row)
     assert len(pkts_data) <= 1, \
-        "Several problems found: {1}".format(
+        "Several problems found: {0}".format(
         json.dumps(pkts_data, indent=4))