Change in company policy and did not officially notify employees. What are my rights?

The company I work for just updated their policy to include drug testing of all newly hired employees and random drug testing among current employees. Prior to this there hasn't been a policy regarding drug testing of employees. They did not officially make aware to us that this was going to happen and we were only unofficially notified via a piece a paper on a bulletin board written by a boss of low stature in the company. Everywhere else I worked when a company made a major change to their policy such as this they had to officially notify us by calling us together to go over, read, and sign that we understand the new change. This was not done and it seems illegal, to say the least. My overall question is this then, what exactly are my rights vs their rights should I be drawn for a drug test and refuse to take it since when i originally joined the company and signed off on the company policies then it was not included. Oh and I live in New York which does not have a law regarding work related drug testing.