well, its not really *supposed* to fail -- there is no exception, it just doesn't give the "expected" result.  that second part isn't really a unit test at all, its just documentation of why this method is needed.  probably doesn't belong here at all, I just wanted it as part of the pull request to demonstrate why the method was needed.

I guess I can just write it up somewhere else (seems too long to put in the spark docs also, at least in the current layout ...)