Adding a few tests which I would expect to succeed?

Frank, I've added a few tests, two of which fail -- but I would have expected
(based on the code, as I read it) to succeed.  If you don't think they should succeed,
can you add some comments to that effect on the relevant methods?

(Or it's possible I already missed comments to that effect in the code, in which case feel free to direct me to those :-) )