It is annoying when dealers do this. Expect you to buy after just a few minutes round the block.
I've found Audi one of the best. Chucked me the keys and said to bring it back once it runs out of fuel. BMW were also very good. Wanted a set time to bring it back, but I could chose the time.
Ford were ridiculous. I could test drive the car (Fiesta ST) for as long as I wanted, just as long as a salesman sat in the car with me throughout. Having to make small talk for a couple hours, and wasn't able to test drive the car as I wanted to. And it took me over a year to get a test drive. Constantly lied to saying they had an ST in, then you find out it's only an ST-Line. Or phoning up on the morning I'd arranged to test drive an ST, that the salesman who has the ST doesn't work on Tuesdays. So why book me in for a test drive of the ST on the Tuesday? Annoying.
Mercedes were the one who though a 10 minute test drive was good enough for me to buy an A35 AMG. Even though before hand I asked for an extended drive. I did eventually get the car for a few hours, after the salesman realised I wasn't going to buy based on a 10 minute drive. I'm pleased he did give me the car, as it made my mind up that it wasn't quite the car for me.
In times where car sales are down, you'd think they'd be desperate to get people out in their cars.