TOPIC:

I found this small servo tester on a chinese site (wish without doing ads)
For very cheap. 1 or 3€ .
Able to test servos and esc, 3 servos simultaneous.
3 functions, manual, neutral and wipper function.
It works very well.

I have a couple of those - the only issue I've found is that they default to the "Man"(ual) mode, so the position of the servo is dependent on the position of the rotary potentiometer, which is annoying if you've only plugged a servo in to make sure it was in the neutrao position for a build and forgot to cycle through to "Neutral"...

I use it to have the neutral position and to be sure that my old servos are ok.
I don't find the interest of the wipper action.....