This test fails on MacOS X. The failure has something to do with
the tests expecting filesystems to accept/store filenames as
bytes. On the HFS+ filesystem, however, filenames are Unicode
characters (Normalisation Form D).
This wget ticket appears to be relevant
http://savannah.gnu.org/bugs/index.php?27541
The maintainer does not seem to think that this test
failure represents a problem in practice:
http://article.gmane.org/gmane.comp.web.wget.general/8988
But this patch should be revisited/removed if this aspect of wget is
ever addressed in the future.
NB: I'm also a bit concerned/confused that none of the tests mentioned
in that message seem to fail, so I'm not 100% sure if this is the
relevant issue.