Personally I purchase most of my stuff used. Some online orders. Often requiring repairs or upgrades. Bare frames? I generally don't depend a lot on the test ride.
However, I would expect the shop to work with you to find a "similar" bike to try out.
The problem comes in with custom order.
If you're coming in with a mid-range bike (for someone in say 5'6 to 6'0), then they may accept a sale with a small non-refundable deposit, and contingent on the test ride (but, anticipating a committed buyer).
But, if it is a unique order of something they expect to be difficult to resell, I'd expect a quite a firm commitment, and perhaps full prepayment.