Handbags   (The sad, the bad and the ugly. Non-productive stuff here.)

Not necessary!

A bad battery can give a misleading high voltage reading, but be unable to source adequate current if polarised, or otherwise high internal resistance.

BUT
A BATTERY WHICH DOES NOT YIELD A USEFUL VOLTAGE even on no load test, then YOU KNOW IT IS SPENT!

The reason I test them rather than just swap them is because occasionally, it is not the battery in the chime unit, but the battery in the bell push (cordless) that requires swapping.

The latter last much longer, as only deliver current when the bell push is actually pressed. (They last about seven years)

My question was NOT about testing batteries. I asked if anyone else had come across the rare phenomena of polarity inversion.