test-driven-development

Test-driven development improves software quality during refactoring by enforcing the Red-Green-Refactor cycle, ensuring production code changes are validated by existing tests to prevent regressions before deployment.

To start writing tests first, create a failing test that defines the desired behavior, then implement the minimal production code required to make that test pass, structuring new feature work through the Red-Green-Refactor cycle.

Yes, you can apply test-driven development to both bug fixes and new features across software projects, using guardrails and checklists to guide teams through writing a failing test before implementing the actual fix or feature code.

The Red-Green-Refactor cycle is a test-driven development process where you write a failing test, implement minimal production code to make it pass, and then refactor the code while maintaining test coverage to ensure reliable feature delivery.

You should not use test-driven development when exploratory prototyping requires rapid iteration without test constraints, as this discipline enforces writing production code only after a failing test exists, which can slow down immediate architectural discovery.