test-driven-development

Test-driven development prevents regressions by enforcing a failing test before any production code is written. This creates a safety net that validates behavior during refactoring, ensuring existing functionality remains intact while changes are applied.

The red-green-refactor cycle in test-driven development is a workflow where you write a failing test, implement minimal code to pass it, then clean up the design. This iterative process guides feature development and ensures continuous test coverage.

Start writing behavior-driven tests by defining the desired API shape and interactions through a failing test. This test-first approach drives the interface design directly from expected behavior, ensuring the implementation matches actual usage requirements.

Yes, test-driven development can be applied to both bug fixes and new feature work across any project. For bug fixes, you write a test that reproduces the defect first, then implement the minimal code correction to make it pass.

Writing a failing test before implementing production code ensures the test actually validates the new behavior and prevents false positives. This practice guides software design by forcing you to define success criteria and expected outcomes upfront.

A limitation of the test-first development workflow is the initial slowdown in feature delivery speed due to upfront test creation. It also requires strict discipline to maintain minimal production code and continuous refactoring without breaking existing tests.