Drug Testing in NHL?

I understand that performance enhancing drugs are a big deal in a lot of sports. But I am wondering, in particular, about the NHL.
1) Do players get tested often? When? And for what?

2) Is it legally allowed for drugs (street drugs) to show up on their tox screen? If it is off the ice, I assume it is still illegal (maybe by law, but I am asking about the NHL’s rules of what is legal and what is not). Do they test the players primarily for steriods or for everything?

3) As a professional, obviously, you are not supposed to be drinking or smoking. However, if the player was to do this, would they be punished?

Thanks.

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