test-driven-development

Test-driven development starts by writing a failing test that describes the desired behavior, then writing minimal production code to make it pass, and finally refactoring for clarity. This red-green-refactor cycle ensures every line of code is verified by a test before it enters the codebase.

TDD prevents bugs by enforcing a failing test before any production code is written. This catches edge cases early, makes regressions obvious when tests break, and creates a safety net for refactoring, reducing the likelihood of introducing new defects.

Write a failing test that reproduces the bug first, then fix the code to make the test pass. This proves the fix works and prevents the same bug from reoccurring later, since the test becomes part of your permanent regression suite.

Yes. TDD supports refactoring by requiring passing tests before you change code. Refactor with confidence knowing your tests will catch any behavior changes, ensuring the code improves in design without altering its functionality.

Writing tests first forces you to think through expected behavior upfront, leading to better API design and fewer untested edge cases. It also prevents the common rationalization of skipping tests when deadlines pressure you, maintaining code quality consistently.

Yes. TDD is a quality assurance practice that embeds verification into the development cycle. Every feature, fix, and refactor is validated by tests written first, creating a continuous safety net that reduces defects and makes the codebase more maintainable.