The test the armed services uses for AAS is not the same as the ordinary urinalysis you will be getting. It is a completely separate test that has to be ordered and used based off of suspect alone, its not cheap either.
I have been in the Marines for 8 Years, and i cant even tell you how many people i know for a FACT were on AAS, its more common than you think. And i have never seen nor heard of anyone being tested for and/or getting kicked out for AAS.
Few things facts
-keeping gear in your barracks will probably get you caught, even if it is locked up(UN-announced health and comfort inspections, yes you have to be there for them, so you get to watch them unlock your locker and find your gear

)
-Keeping gear in your car can get you caught(random vehicle inspections at the front gate)
-Acting like the typical AAS user this day in age (the 6' 170 lb kid who uses AAS and gains 20 lbs in 2 months) will defiantly get you some unwanted attention, but still not likely..
Use at your own risk, but if you are concerned about being randomly tested like a urinalysis its not gonna happen. you have to give someone with a good amount of rank a damn good reason to think you are on AAS to be tested for it.