Unit testing is the idea of breaking your application into the simplest pieces possible, and then, test it individually, to make sure it all works as inteded. This is what I did with the classes contained into this repository (User and UserTest). You can check the src folder to see the origin classes, and the tests folder to see the test classes and all the methods from PHPUnit that I used.
This repository will most likely be updated with more tests, methods and ideas as time goes on.
Versions
PHP: 8.1.6
PHPUnit: 9.5.27
Composer: 2.4.2