Thank you. This feature is already being considered for a future update. No ETA yet.
-Jeff Herald - Pharos Systems
Technical Product Manager for Uniprint and Mobile Print
Here's a workaround that I've used at CU. Create a specific print group for your test devices. Name them testprinter01, 02, etc. and educate the users that these are "dummy devices". I've done this a few times when we wanted to test against the production system from a specific lab. In our environment, the labs have all the printer queues available, but are set to default to the device(s) in the lab. In order to change that the users must intentionally choose another device within the print preferences. Since the majority of the users never even look at which printer is being used (since it defaults to the ones in the lab), having "dummy printers" amongst the group would likely have minimal impact.