Why are tests written before code in the TDD methodology?

Tests are written before the code for several reasons:

• Requirements definition: Writing a test forces you to clearly define what the code should do.
• Minimizing errors: Tests create a behavior specification that helps write only the necessary code, avoiding overcomplication and potential mistakes.
• Quick defect detection: If a test is written before the code, it will fail before the code is correctly written. This allows for quick identification and fixing of defects.
• Confidence in refactoring: Having passing tests provides confidence when changing or refactoring existing code, ensuring its original behavior is not broken.
• Better design: Focusing on testability from the start often leads to a more modular and maintainable code design.
• Documentation: Tests serve as living documentation, showing how the code should be used and behave.