yes its getting harder and harder to get a job i can see, if you want to do drugs just quit right around the time you get hired and after you get hired start doing them again
I had to be tested before I could start to work at Best Buy. In fact they give you only twenty four hours to complete the tests or your job offer goes away. I don't know if they do random tests, though. I really don't think so. Every day at work is a test in some ways. You could not get away with going slacker up there.
Some drugs remain detectable in your system for up to ninety days, especially pot. If you are a daily user of pot, it could take even longer to leave your system.*
Stopping the use of drugs far enough in advance of a test will get you by in the beginning, but a random drug testing policy, which I think is certainly a crock of shit/invasion of privacy could still catch you if you go back to doing drugs.
They only need a "breath-alyser" (blow through a tube) to find if you are coming to work drunk. Alcohol leaves the body within six hours, most of the time. The chronic drinker may have residual effects for several months after going sober, though.
*BTW, I was talking about a urinary test. If the take hair follicles or fat cells you're fucked.