test-driven-development

Test-driven development is a test-first approach where you write a failing test defining expected behavior, implement minimal code to pass it, then refactor safely. The red-green-refactor cycle surfaces correctness early and encourages clean, maintainable code.

To start writing unit tests before production code, write a failing test for the intended behavior, verify the failure, then implement the simplest code to make it pass. This structured workflow provides predictable validation for feature development.

Yes, test-driven development supports bug fixes and refactoring by requiring a failing test that reproduces the bug or locks in current behavior before making incremental code changes. This improves confidence and reduces regressions across typical software projects.

The best way to ensure code quality and prevent regressions is adopting a test-first mindset with disciplined red-green-refactor cycles. Requiring automated tests to accompany code changes provides structured validation and reduces regressions for new features.

A test-first approach requires writing real tests first and verifying failures before implementation. If a project cannot support automated unit testing or lacks a predictable validation environment, the strict red-green-refactor cycle may not be suitable.