test-driven-development

Test-driven development requires writing a failing test first, then implementing minimal code to pass it. Start by defining what your feature should do in a test, verify it fails, write only the code needed to make it pass, then refactor. This Red-Green-Refactor cycle ensures your tests actually validate behavior and your implementation stays focused.

A failing test proves your test actually works and will catch real bugs. If a test passes without your code, it's not testing anything. Test-driven development mandates seeing the failure first to guarantee the test is meaningful and will protect against regressions.

Write tests first to drive your design. When you test before implementation, you naturally write code that's testable and consider edge cases upfront. This approach eliminates common pitfalls like creating functions that can't be easily tested or missing boundary conditions that tests would have caught.

For each bug, write a failing test that reproduces the issue, verify it fails, then implement the minimal fix to pass. This creates a regression test that ensures the bug won't reappear and proves your fix actually solves the problem.

Yes. Test-driven development applies to new features, bug fixes, and refactoring across all project types. The Red-Green-Refactor workflow and the rule of no production code without a failing test first remain consistent regardless of your tech stack or domain.

Test-driven development explicitly counters rationalization like "tests slow me down" or "I'll test later." The methodology enforces consistent application by making the test-first rule non-negotiable, ensuring your test suite stays comprehensive and bugs stay caught early.