Index: /trunk/src/VBox/ValidationKit/tests/additions/tdAddGuestCtrl.py
===================================================================
--- /trunk/src/VBox/ValidationKit/tests/additions/tdAddGuestCtrl.py	(revision 84570)
+++ /trunk/src/VBox/ValidationKit/tests/additions/tdAddGuestCtrl.py	(revision 84571)
@@ -66,6 +66,8 @@
     """
     if not isinstance(sString, str):
-        return "";
+        sString = str(sString);
     cLen = len(sString);
+    if not cLen:
+        return cLen;
     return (sString[:cLimit] + '...[%d more]' % (cLen - cLimit)) if cLen > cLimit else sString;