Hello r/gamedev, I made this free little tool to test out controller inputs, since there's hardly a way to test them out without running a game or some other unrelated software :
PS4 controller Tester - Apps on Google Play
How to Calibrate Your Gaming Controller in Windows 10
jstest-gtk - A joystick testing and configuration tool for Linux
Gamepad Vibration Test: How to Check Gamepad is Working or Not on PC | Videogamerplus
How to Calibrate Your Gaming Controller in Windows 10
Game Controller Tester on the Mac App Store
How to Use an Xbox One Controller with a Mac
Easy Ways to Test Your PS4 Controller: 9 Steps (with Pictures)