test-driven-development

Test-driven development reduces regressions and guides design by ensuring features are validated by automated tests before implementation. Writing tests first guarantees reliable, regression-safe code across new features, bug fixes, and refactoring tasks.

To implement test-driven development for new features, write one failing test first, then implement the minimal code required to pass that test. Finally, refactor the code while keeping the tests green to maintain reliable behavior.

Use unit testing and test-driven development for bug fixes when you need verifiable outcomes and regression-safe code. It enforces writing a failing test that reproduces the bug before applying the minimal code fix to pass it.

Test-driven development works for refactoring by keeping tests green while you modify the internal structure of existing code. It encourages small, testable units and fast feedback loops to preserve behavior and improve code reliability.

A limitation of enforcing test-driven development is the strict requirement to write failing tests first before any implementation. This practice may slow down initial coding speed for rapid prototyping where immediate verifiable outcomes are not essential.