There's another thread that goes into more detail about this issue. You are leaking coolant, regardless of whether they say so or not. Even pin hole droplet sized coolant leaks will have a pretty strong odor. You are more than likely seeping coolant onto a hot part of the engine and it's burning off to fast to have any visual signs.
As far as the pressure test, my car passed the first time around as well. I took the car to a different dealership with more competent techs who left the tester on the car for over an hour. Eventually there was a notable pressure drop on the system, it just took some time for the readout to show. I was having the same issue, slowly losing coolant. Water pump / thermo housing replaced under warranty. To this day, I still smell coolant, but I'm not losing any at this pint.
Please also note that there is a vent on the top of the coolant reservoir as well. Little arm like looking piece of plastic covering a small vent hole. I'm not sure why it's designed this way as coolant systems are supposed to be considered "sealed" systems, and if they are pressure testing them, I don't know how it would be possible unless it was sealed. This is just what I've been told by the dealership.
Raise hell and tell them to leave the tester on the car for longer. If you are losing coolant over time, you have a leak.