diff --git a/test/mock_high_priority_service.hpp b/test/mock_high_priority_service.hpp
index c228c70..2d3b760 100644
--- a/test/mock_high_priority_service.hpp
+++ b/test/mock_high_priority_service.hpp
@@ -34,7 +34,7 @@ namespace wsrep
         void adopt_transaction(const wsrep::transaction&) WSREP_OVERRIDE;
         int apply_write_set(const wsrep::const_buffer&) WSREP_OVERRIDE;
         int append_fragment(const wsrep::ws_meta&,
-                            const wsrep::const_buffer& data) WSREP_OVERRIDE
+                            const wsrep::const_buffer&) WSREP_OVERRIDE
         { return 0; }
         int commit() WSREP_OVERRIDE;
         int rollback() WSREP_OVERRIDE;