Higher end strains, as found in dispensaries, are often bred for the desired balance of components, so you can just ask your vendor at the counter.

I don't know how well-tested these strains are (aside from, "puff... yeah, man, that's awesome"), but there has always been a desire in the medical marijuana market for selection based on this data which I'm sure carries over, so I suspect that now that it is legal in a couple of places, we'll begin to see Consumer Reports style testing. Hell, maybe even the Consumers Union, themselves, will get on the case.