In particular, the tests that use output_test_stream supply filenames that are interpreted relative to the current working directory. That's not the best possible practice, for reasons of "hygiene:" if testing Boost causes the Boost tree to be modified, it's hard to be sure that one is testing the same thing the next time around. Furthermore, it means one can't test from within a read-only copy of the Boost sources. This bit me as I tested from an NFS-mounted working copy. I realize that Boost.Test may not want to depend on something like Boost.Filesystem, but it seems to me that any decent testing framework has to be able to get ahold of a temporary directory anyway, so maybe the ability to create files in /tmp or %TEMP% should be part of the library? -- Dave Abrahams Boost Consulting http://www.boost-consulting.com