I'm currently mocking a lot of SystemWrapper types- and I've begun using MEF to glue it all together.
Do you envisage any future support for MEF or for another dynamic container??
I'm pretty sure I can get it working as is, however it would be so much cleaner if SystemWrapper defined exports.
public class DirectoryWrap ...
It would mean all though dependencies that are declared when you begin to mock system types, magically resolve themselves.
Anyway, it's just a thought.