Unit testing with PHP Unit. If you are a PHP developer and you want to learn how to write better code, with fewer bugs, you will need to know how to write unit tests.
Learning how to write unit tests for your code will make you write better code. With automated tests, you can find bugs more easily, and if you break something you’ll notice it straight away.
Learn how to unit test your PHP code using the PHPUnit testing framework.
Use test doubles: mocks and stubs, including how to use Mockery
Many experienced developers write unit tests for their code. It’s a repeatable way of checking that the code works as intended, and also serves as documentation. Many popular PHP projects are unit tested, such as WordPress and Moodle, and if you use frameworks such as Laravel or Symfony, these provide tight integration with the PHPUnit testing framework.