If you use a sensible test station then the days of failing for a 1mm tear are long gone. At least since computerisation & the availability of the test manual online (so well over a decade now), the criteria has been:
"A wiper blade insecure, missing, or in such a condition that it does not clear the windscreen effectively to give the driver an adequate view of the road (through the windscreen) to the left and right sides of the vehicle, as well as to the front."
A genuine 1mm tear comes nowhere near that decription. I've put cars in with a good 10-20mm cut off the blade as a temporary measure (stops the annoying flapping and helps stop them tearing further) without any problem.
Under the new rules you can get a "minor fail" for ANY damage but only a fail fail for "missing or obviously not clearing the windscreen". Again, a 1mm tear isn't going to meet that requirement.
If you've had problems with this sort of item with your current tester then you need to change your tester not the wiper blades!
eta: And, no, rear wipers aren't testable still.
Last edited by Joe Horner; 17-05-2018 at 11:25 AM.