diff --git a/test/functional/interface_rpc.py b/test/functional/interface_rpc.py
--- a/test/functional/interface_rpc.py
+++ b/test/functional/interface_rpc.py
@@ -54,7 +54,7 @@
             # work fine.
             {"method": "invalidmethod", "id": 2},
             # Another call that should succeed.
-            {"method": "getbestblockhash", "id": 3},
+            {"method": "getblockhash", "id": 3, "params": [0]},
         ])
 
         result_by_id = {}