Test Driven Development (TDD) is a software development technique where unit tests are written before functional code to verify functionality. The TDD process follows a "Red, Green, Refactor" cycle where tests fail initially ("Red"), code is written to pass tests ("Green"), and code is refactored to improve design. While TDD may improve code quality and catch errors earlier, studies have shown mixed results on productivity and quality improvements. Adopting TDD fully can be challenging in practice due to issues like incomplete test coverage and resistance to change.

1. Test Driven Development THEORY • FACTS • APPLICATIONS • SUPPORT ALEXEI PIVKINE • YURIY POSLAVSKYY • SWARAJ SHERGILL • QING WEI Group 2

5. Test Driven Development Cycle

11. Impact of TDD Other Case Studies