I confirmed with Etihad today about Hyd - Abu Dhabi (6 hours layover) - Toronto route and they said that its functioning now. They even said that Etihad will make sure that the test is getting done in this 6 hours layover. Youtube videos suggested that they even delayed the flights by few hours because test results of some passengers were delayed, just to ensure that everyone is able to fly board the flight. As my classes are online, I booked my tickets in Oct just for 47k with student discount and 23x3 luggage.This is 6 hours now for India passenger as I checked but all flights have 6.5 hours layover checked with etihad they said that should be alright
Note that this facility is not available from New Delhi as the layover is only 4 hours and not sufficient to get the results.