It depends on the cop. Weed is still illegal in Canada. Some cops will let you go if it's just a little bit, others won't. It's the same as it is anywhere. Some areas in Canada are more lenient while some aren't. Similar to the US and any other country where weed is illegal. Some cops don't care, some do.
But yeah, no drug testing in Canada, never even thought of that really, unless you're in a really intense position. But for most jobs, no drug testing. I didn't even know drug testing was a thing until I read about it online.