Test-Driven Development (TDD) is a software development methodology where writing tests is a central part of the development process. The core approach of TDD is to write tests before actually implementing the code. This means that developers start by defining the requirements for a function or feature in the form of tests and then write the code to make those tests pass.
The typical TDD process usually consists of the following steps:
Write a Test: The developer begins by writing a test that describes the expected functionality. This test should initially fail since the corresponding implementation does not yet exist.
Implementation: After writing the test, the developer proceeds to implement the minimal code necessary to make the test pass. The initial implementation may be simple and can be gradually improved.
Run the Test: Once the implementation is done, the developer runs the test again to ensure that the new functionality works correctly. If the test passes, the implementation is considered complete.
Refactoring: After successfully running the test, the code can be refactored to ensure it is clean, maintainable, and efficient, without affecting functionality.
Repeat: This cycle is repeated for each new piece of functionality or change.
The fundamental idea behind TDD is to ensure that code is constantly checked for correctness and that any new change or extension does not break existing functionality. TDD also helps to keep the focus on requirements and expected behavior of the software before implementation begins.
The benefits of TDD are numerous, including:
TDD is commonly used in many agile development environments such as Scrum and Extreme Programming (XP) and has proven to be an effective method for improving software quality and reliability.
PHPUnit
