How can you check whether a MacBook Pro turns off screen when closed?

Question

It may not turn off the screen if there is a hardware or software issue. So is there a way to check?

nonrandomstring · Accepted Answer

I cut a window in my fridge to make sure the light goes out (and the yogurts aren't partying after midnight).
But because I am worried about observer effects [0] I sometimes hide around the corner and jump out on the fridge to try and surprise it,
So far, all quiet.
[0] https://en.wikipedia.org/wiki/Observer_effect_(physics)

dave4420 · Answer

Close the lid slowly, while keeping your eyes in a place so you can still see the screen and the keyboard. The screen will turn off before the laptop is completely shut.