> I like that. It fits well with the principle of locality ("things that
> are semantically close should be physically close"). One 
> drawback might
> be that loading time&space gets increased. The latter is probably
> avoidable if test() does nothing when user is not in "test" mode.

If the tests are in a separate file, appended to the class, then when not in
'test' mode, that file won't be loaded.

Chris