State side most local parts stores have testing equipment and can check them in house for free. Not sure if that's the same up north.
-Tim
AutoZone used to test them here in the PNW, with vague success...about 4 years ago they went full stop and declined to test them at all. This was about the same time the price fell dramatically, and with lifetime warranty, the last time I had doubts on one I'd bought from them, they just gave me another.
I've a bag full of used ones I haven't touched in a long time, and I'm currently trying to come up with a better way to bench test, however, as that would involve feeding it live signals and getting it up to temperature, on-car testing is still easier, but not as easy as taking advantage of a free replacement warranty, so...
My goal with being able to reliably bench test is still on due to anticipation of these being obsoleted any day now, and when that day comes, a warranty won't matter.
About DIS fails, since we're on the subject - I think the reason it's common to have a box/bag full of spares is that the DIS gets side-eye as culprit when swapped and things work better because of other issues, such as a compromised harness or marginal grounding. Simply swapping one out can cause changes in those, making it seem like the DIS was the problem, when it was just caught up in the root cause. I wonder if any of the spares I have include one hard fail, but that day will come, and that box of spares will be money in the bank when these things are no longer available, just like the early crank sensors.