The flashlight sits on a tripod 1m from the wall (from the lux meter, to be exact) with the same hight as the lux meter’s sensor. The flashlight never moves.
First the beam pattern is measured by moving the lux meter from left to right and taking measurements in pre-calculated distances from the center. Starting on the very left (1m from the center, representing -45 degrees), moving towards and passing the center (0 degrees), all the way to the right (1m from the center, representing +45 degrees). The lux meter is turned every time to face the light souce directly.
Then the runtime is measured with a fresh set of Eneloops. The lux meter is put back to the center and the flashlight points at it directly. An action cam is used to record the readings in 1min intervals (My lux meter has no data logging capabilities).
Finally the measured data are typed into this spreadsheet and the calculated lumens, throws, floods, and runtimes are graphed.
PS.: In case you were wondering, yes, those are my underneath bed drawers holding the tape measure and the lux meter. They happen to be 1m wide, so I use them in my test setup. :-)