diff --git a/test/message/call.cpp b/test/message/call.cpp
index 4cd82ac..376d128 100644
--- a/test/message/call.cpp
+++ b/test/message/call.cpp
@@ -28,8 +28,8 @@
 
 std::string syncBusId(bus_t& b)
 {
-    std::string ret;
-    newBusIdReq(b).call().read(ret);
+    auto ret = newBusIdReq(b).call().unpack<std::string>();
+
     return ret;
 }