Test driving a new car and towing with it.

Everyone on here chooses their car for 2 things normal driving and towing,unless you have a second car just for towing,I wish dealers would allow you to tow with the car your test driving,i don't mean bring your caravan along but the dealer have a trailer with a known weight 1500kg eg. So we the buyer can actualy feel what the car is like when towing not just read about it in articals and forums.has anyone been allowed to test drive while towning?