Funny thing about the drug tests when first required. 

I belonged to Midwest Truckers for administration.  In the instructions, I had to keep secret the time the drug tester would arrive at my work location.  They included me in the drug testing, I would be informed of when it would happen, and I was not to tell myself.  Later they exempted owner-operators from the drug test.

My employee was not to be informed, they had to inform me so I could be sure he would be present for the test.  The person giving the test would come to my machine shed, and the employee would go in the corner and complete the test.  Didn't take long to do this, no big hassel.

At first, I silently objected to the test.  Then I realized the purpose of the test was to keep inpaired drivers off the road.  I sure don't want to be in a car in front of 80,000 pounds of truck driven by an impaired driver!