TDD in practice with PHPUnit

TDD has become an essential practice for developers to have more confidence and engage practices such as refactoring. For example, if you updated some critical library in our application, you can run all tests to see if some implementation has been broken. According to wikipedia: Test-driven development (TDD) is a software development process that relies on the repetition of a very short development cycle: first the developer writes an (initially failing) automated test case that defines a desired improvement or new function, then produces the minimum amount of code to pass that test, and finally refactors the new code to acceptable standards. »