test-driven-development

Test-driven development is a software development process that requires writing a failing test before implementing production code to define expected behavior upfront and prevent undetected bugs.

To apply the red-green-refactor cycle, write a failing test defining the new behavior, implement the minimal production code to pass it, then refactor safely to maintain quality.

Use test-driven development during bug fixes and refactoring to validate behavior before implementation, preventing regressions and improving maintainability across software projects.

Test-driven development does not mandate specific testing frameworks; it requires writing a failing test first, then implementing the simplest production code to make it pass.

The best way to start writing tests before implementation is to define the expected behavior with a failing test, then implement the minimal code required to pass that test.

Writing tests first improves software quality by enforcing test-driven development, which validates behavior before implementation and prevents regressions during subsequent feature work and refactoring.