I'm doing a little white boarding for testing.

 

I would like to load the Pi power supply so that it draws the maximum current possible before I go to PoE. That maximum draw state becomes my test condition when operating from the PoE. This configuration would put the maximum strain on the PoE Hat under test. My thought is a maximum CAT5 cable length while under maximum draw is a good performance check for the unit.

 

Powering LED’s connected to all GPIO’s and taxing all CPU cores is my thought. Now to figure out how to do that.

 

Note to self...think about heat dissipation. I seem to recall Pi4's throttle when they get hot. Run similar test using Pi3B+ will provide some additional information.