I do not follow EV Cars testing, but I did spotted at one company in Holland this be a developer of EV Cars testing process.
That they did adopt a Made in Taiwan Insulation Resistance Tester.
And they use 1000V testing at the pins of the charging port.
EV Cars testing process, this becomes today an extremely dangerous profession for any involved electrician.
Special rules apply, so the car to be first electronically deactivated, prior of any electrical inspection.