So the logical extension is that a car test has to include an emergency stop on a wet road. Could be interesting!
Erm... but they do already... if it happens to be raining, don't they?
Same as the bike test... they don't chuck a load of water at you to simulate wet weather conditions... it's just if you're unlucky enough to have bad weather on your test day, you have to lump it.
They already cancel driving tests in extreme weather conditions e.g. snow/ice and presumably the same applies to bike tests? I don't know, as I've never done a bike test... yet