I am most reliably advised that the FAA inspect Repair Stations over here, once a year, and have been doing so for years.
Doing it twice a year would be an irrelevance.
The random drug testing is indeed likely to be illegal over here, but it is probably illegal over there too...
However it is pretty obvious that nobody would actually bother doing it in "civilised" Europe, because drug abuse is hardly an issue in aircraft maintenance. Are there EU countries where it may be an issue? There are some pretty dodgy EU countries but I still don't see it being an issue - if you do anything better than totally idiotic recruitment.
So I think there must be some other bollox the EU is trying to achieve...