Application will assist you in checking a used phone quickly. The necessary information about the hardware and software will be faithfully displayed as well as a way for you to check the device step by step.

Features
Screen test: check the brightness, burn-in error or light leak, test white, black, blue, red, yellow… Check for dead spots on the screen.
Touch screen test: touch all the points on the screen.
Multi touch screen test: tap the screen at once with as many fingers as possible.
Check all camera: mega cam, front cam, auto focus, look if the camera is dusty or scratched.
Check flashlight: flash next to the camera.
Check vibrator: take your phone and see if it vibrates.
Check pressure: press the phone screen and then release your hand, if the pressure parameter changes, the pressure will still work.
Compass sensor: try rotating the phone in multiple directions
Device info: android version, phone's name, device's code…
And more