The tests that deal with Moo are there because Moo directly uses Role::Tiny, so we have to be certain that compatibility is maintained. Role::Tiny isn't ever really going to account for interactions with Moose. If proper integration of modules using Role::Tiny and Moose is needed, Moo is the compatibility layer to allow that.
I don't see any value in testing that inside Role::Tiny, so I'm rejecting this.