When you agree to work for a trucking company you agree to random drug testing. You keep saying called... (Not sure if you literally meant the call or actually taking the test immediately) They can call you about it of course but you don't have to answer if you're sleeping.
Typically notify you when you are on duty, just finished or about to start duty. After some time away if they have reasonable suspicion of drug abuse they can also test. (But it wouldn't be a random. So I digress...)
I don't know if they can get you out of the sleeper/bunk or interrupt your 10 hr break to do it unless you still have time on your clock.
But as soon as you have available time to go on duty, you are definitely obligated to take the random or it's a refusal. (Of course going to take the test is on duty hours)
The sensible thing for them to do was just wait until your off duty time was up. But not all company policies are sensible. Plus, they might have called prior to make sure that when you went on duty you went straight to testing sight prior to performing normal work duties.
The whole point though is to catch you off guard not give you advance notice to prepare for it. (That's why it's a random)