test-driven-development

Test-driven development prevents regressions by requiring a failing test to exist before any production code is written. This verifies expected behavior early and ensures iterative safety checks during feature development, bug fixes, or refactors.

To write tests first for new features, begin by writing a failing test that encodes the desired behavior. Observe the failure, then implement minimal production code to pass the test, and refactor safely to maintain quality assurance.

Yes, you can use test-driven development for refactoring existing code. Write tests to verify expected behavior before modifying production code, ensuring that your refactoring efforts do not introduce regressions or break existing functionality.

Test-driven development works for fixing bugs in any codebase by enforcing a failing test that validates behavior before writing production code. This ensures the specific bug is captured and prevents future regressions from occurring.

You should avoid test-driven development when exploring exploratory prototypes or throwaway scripts where verifying long-term behavior is unnecessary. The workflow enforces minimal test-passing implementations, which may slow down rapid, unstructured experimentation.