Mac OS filesystems store filenames only in normalized UTF-8. Various tests of the IRI support in Wget save filenames that do not match these requirements and are automatically transformed; the test harness is then surprised when the filenames don't match the expected ones, and the tests fail.

The ones that force --local-encoding to a non-UTF8 value should be changed to avoid forcing local encoding on such a system; if they need to test conversion between remote and local, then remote should be changed to something else. The test harness should be modified to translate expected filenames into the canonical representation before matching.

See http://article.gmane.org/gmane.comp.web.wget.general/8984