The i18n tests are disabled if they are running in non-English locales. It would be good to have them running regardless of the locale.
In Ole's nightly tests they are not running on Windows because of this. Seen for example last night when the i18n tests failed on all platforms, except on Windows:
There have been various improvements in ScriptTestCase lately to allow the canon-based tests to run in non-English locales, so I think it's safe to enable them now.