In protected mobility vehicle, both Mahindra and TATA has undergone extensive trials along with Kalyani.I would assume Mahindra already undergone those tests.. since its been acquired for UNOPS as well as frontline in limited no.
Any chassis change required homologation again and again series of tests. Remember even Mahindra's current vehicle is reworked Israeli AXE - and undergoing trials for more than decade for every iteration. Tata will undergo the same.
In Multipurpose vehicle category, none has undergone any tests.