diff --git a/libraries/AP_SerialManager/AP_SerialManager.cpp b/libraries/AP_SerialManager/AP_SerialManager.cpp
index 1b04c6d0b5..64e9345481 100644
--- a/libraries/AP_SerialManager/AP_SerialManager.cpp
+++ b/libraries/AP_SerialManager/AP_SerialManager.cpp
@@ -19,7 +19,7 @@
   serial ports and provides helper functions so objects (like a gimbal) can
   find which serial port they should use
  */
-
+// this is to test
 #include <AP_HAL/AP_HAL.h>
 #include <AP_Math/AP_Math.h>
 #include <AP_RCProtocol/AP_RCProtocol.h>