Hello,

I think this deserves a "how did this ever work" award :-)

The file was being created writeable (the S_IWUSR flag passed to open()) 
so little wonder GNU/Linux allowed an open-write (causing the test to 
fail) and who knows how/who this worked on BSD and remote systems.

Tested on BSD and GNU/Linux.  Baring comment I'll commit in a day or so.

Andrew