Test-driven development (TDD)

Test-driven development is the process of testing every aspect of the application during development. Either the tests are defined before development and then development is made to pass these tests, or the classes and libraries are built and then tested. Testing the application is very important, and launching an application without tests is like jumping from a 30-floor-high building without a parachute.

PHP does not provide any built-in features to test, but there are other test frameworks that can be used for this purpose. One of most widely used frameworks or libraries is PHPUnit. It is a very powerful tool and provides lots of features. Now, let's have a look at it.

The installation of PHPUnit is easy. Just download it and place it in your project root so that it can be accessed from the command line.

Note

PHPUnit installation and basic details, including features and examples, can be found at https://phpunit.de/.

Let's have a simple example. We have a Book...