Thanks GrandFather, that may well be what i am looking for. I can will try to incorporate tests into the objects so that they can make sure that the code refs haven't gone funky and that the data the objects hold hasn't changed either.

I guess subclassing a specialised My::Mod::WithTests class, which includes testable data and expected code ref output, would be the best way to do this? then i can include a few 'testable' objects in the larger collection. Or would a run_tests() method be enough (again including specialised test data and expected ouput)?

I'll take into account perrin's advice too, see if i can't avoid this whole thing somehow. Or at least strip down the serialized data to a simpler format, only including the key data, and have a new_from_skeleton() method...

Thanks everyone for your input!