[MrSurly]

The sad bit is that there isn't a definitive VR test, only elimination of other things until we have to get to the conclusion that it must be the VR.

The stator CAN be tested and can be conclusively failed if it tests Open (A to B, A to C, B to C) or Shorted (any of them to case ground)
Here's something often overlooked, I think, when testing a stator.
It is possible for a shorted stator to appear to test "good". Here's how to make certain that you're getting a proper test.
Your volt meter has a "diode check" or basic continuity test position; usually with an audible alert to let you hear that is "sees" a connection across the leads or whatever conductors you are testing. This is the setting that we default to when checking for burned fuses and such because it has the handy beep. This will "see" a connection if the connection is pretty good. A shorted stator *might* be shorted rather severely, resulting a very detectable connection to ground, less than 50 ohms of resistance, say. This will cause the beep sound and you will know, without a doubt, that the short is there and the stator is bad.
But it can also be the case that the stator is shorted *just a little bit*. The beeper will not sound because the setting on the meter is in the wrong range and can't 'see' the weaker connection. No beep, so you'll call it good and then go buy a VR. And then later discover that the stator was bad all along.
To avoid this unhappy circumstance, simply switch the setting on your meter to its highest resistance setting (likely 400K ~ 10Megaohm) And check for a shorted stator again. The beeper will likely not even operate in this setting, so watch the digital readout.

Note 1.) that the stator winding FAILs the test if there is any connection to ground detected. the readout should remain 0.0
Note 2.) also that in this highly-sensitive setting that moisture in the connector or leads or even your fingers touching the leads will cause a reading.
( you can measure the conductivity of your body at around 200~ 300K ohms. as well)
Note 3.) Using this range of measurement is the primary reason the meter has that big-assed 9Volt battery. Make sure that yours has a good fresh battery to get the best test.

P.S. Mike! Thanks for the company down here in the service line.