At first glance, a luminaire seems simple. It turns on. It lights things. Ideally, it plays nice with others and doesn’t turn your ceiling into an inferno 

But somewhere between “light bulb” and “modern luminaire,” the tech escalated. Now you’ve got power supplies, LED arrays, optics, thermal management, and mounting hardware all crammed into an unassuming fixture that’s expected to draw as little attention to itself as possible for years. Come heat, cold, or ceilings that haven’t been inspected since 1998, that puppy better turn on and off – beyond a shadow of a doubt. 

https://productsafetyinc.com/frequently-asked-questions-about-luminaire-testing/