PHPUnit is a one type of unit testing framework for PHP language. In todays PHPUnit is very popular for testing. Most of site owner want to implement PHPUnit test because that way we can simply test using command. Without testing our website will never be good to publish. But if you don't know about PHPUnit and no idea how to start so just follow bellow example for scratch.
I will give you very simple example of PHPUnit and how it works from scratch. I make quick easy example with phpunit command. We have to create two file like as listed bellow: