Debug inputs and outputs

Hello, just finished soldering my Pedal-Pi (for the first time soldering something).

I want to check if the components are working properly but separately, that I can check every button, led, and the toggle switch in every state, without running the sound effect scripts.

im running it on a pi zero 1.3 without wifi, means i need to connect it to the Pi3 for the installation and adding the scripts, then move the SD to the pi zero.

secondary, because its my first soldering, im not sure i did it properly, this also need to be checked.

does anyone knows a script for it?
help, something?

thanks

Im not getting any signals, also dont have enough place in my only SD card for the premade image.

Do you think its okay to install Raspbian lite, and the basic codes on RPI 1 then move the SD card to the zero 1.3?

TRIED HARDER & EDITED:
I have managed to activate the testing script.
all the triggers work fine but the ADC's value, in the documentation is written that i need to get a value of between 1800 and 2100. for some reason i get 0.

what might be the reason?

thanks.