Test-Driven Development (TDD) represents a software development process where automated tests are written before the code they are designed to verify. This practice reverses the traditional development workflow, prioritizing the definition of requirements and expected outcomes through test cases, before the creation of the application logic itself. As a concrete example, before implementing a function to calculate the average of a list of numbers, one would first write a test that asserts that the function returns the correct average for a given set of inputs.
The significance of this lies in its ability to drive design and ensure code correctness. By focusing on tests first, developers gain a clearer understanding of the desired functionality, leading to more modular, maintainable, and testable code. Historically, its adoption has been linked to improvements in code quality, reduced defect rates, and a more agile development process. The iterative nature of TDD, involving cycles of “Red” (test fails), “Green” (code passes test), and “Refactor” (code improvement), encourages continuous improvement and reduces the likelihood of introducing bugs.
