api call 'test' doesn't anymore.

According to the current Twitter REST API here - http://apiwiki.twitter.com/REST+API+D... - there is an API call that was set up to test - presumably to test that Twitter is up. Here's the writeup on it -

> Help Methods
> test
>
> Returns the string "ok" in the requested format with a 200 OK HTTP status code.
>
> URL: http://twitter.com/help/test.format
>
> Formats: xml, json

Today it has suddenly started returning this:

[url] => http://twitter.com/help/test.json
[content_type] => text/html; charset=iso-8859-1
[http_code] => 301

Which jumps to this page: http://help.twitter.com/portal

This is strange behaviour - it has worked fine for the past week. Other API calls seem to work - looks like someone just messed with the site address.