diff --git a/src/utils/BusMaster.hxx b/src/utils/BusMaster.hxx
index b6f33e7b2..96b59617f 100644
--- a/src/utils/BusMaster.hxx
+++ b/src/utils/BusMaster.hxx
@@ -96,6 +96,12 @@ public:
         {
         }
 
+        /// Used in unittests to cleanly shutdown the bus master.
+        void request_shutdown()
+        {
+            needShutdown_ = true;
+        }
+
         /// Used in unittests to cleanly shutdown the bus master.
         void shutdown()
         {