--- a/tests/autodiff.py	Tue Nov 20 14:21:56 2012 -0800
+++ b/tests/autodiff.py	Sun Nov 25 13:53:47 2012 -0600
@@ -35,7 +35,7 @@
     for chunk in it:
         ui.write(chunk)
     for fn in sorted(brokenfiles):
-        ui.write('data lost for: %s\n' % fn)
+        ui.write(('data lost for: %s\n' % fn))
 
 cmdtable = {
     "autodiff":