Andrew, you shod a flea.
1. Now the test skipped on non Cyrillic-compatible locales (such as en_US.ISO-8859-1).
2. On UTF-8 locale the test does not test the bug (it passed even without the patch).
Here is a new patch. It should fail on FreeBSD with ASCII locale (because there is a yet not fixed bug), and I don't know how it will behave on Windows. Temporary you can explicitly skip the test for such case:
@unittest.skipIf(sys.platform.startswith('freebsd') and
sys.getfilesystemencoding() == 'ascii',
'skip on FreeBSD with ASCII filesystem encoding')