test-driven-development

Test-driven development fixes bugs by reproducing the issue with a failing test first, then implementing the minimal code change needed to make that test pass. This proves the bug exists before you fix it and prevents future regressions.

The RED GREEN REFACTOR workflow is a test-driven development cycle where you write a failing test, implement the smallest code change to make it pass, then refactor without altering behavior. This ensures logic remains correct throughout development.

Unit testing versus integration testing depends on boundaries and user-critical flows. Use unit tests for isolated logic and integration tests for interactions across boundaries, following the test pyramid to keep tests fast, reliable, and meaningful.

Prevent regressions during refactoring by relying on existing tests to prove behavior remains unchanged. Test-driven development ensures you refactor only after tests pass, maintaining correctness while improving code structure without introducing new bugs.

Yes, test-driven development supports browser testing for front-end behavior. It includes browser runtime verification to ensure user interfaces function correctly, adding E2E tests for critical flows alongside unit and integration tests.

Test-driven development requires writing tests before logic, which can slow initial development. It demands deterministic isolation and state-based assertions to avoid flaky tests, and may not suit exploratory prototyping where requirements are highly unstable.