Can't imagine trying groupsets (*can't quite get my mind away from the idea of trying groupsex) is an easy thing to do, in terms of a test ride?!? But i'm guessing what you're saying is to try and check out a selection of hoods and see how their shifting feels.
All the levers are very different between brands... just going in and getting your hands on the levers in the shop, maybe shifting up and down one gear and pulling the brake can help you choose. It's definitely a matter of personal preference as you can see on this thread :)
Can't imagine trying groupsets (*can't quite get my mind away from the idea of trying groupsex) is an easy thing to do, in terms of a test ride?!? But i'm guessing what you're saying is to try and check out a selection of hoods and see how their shifting feels.