test-driven-development

Test-driven development for a new feature requires writing a failing red test first, implementing minimal production code to pass the test, and then refactoring for clarity while keeping tests green.

The red-green-refactor cycle is a testing discipline where you write a failing red test, implement minimal code to turn it green, then refactor the code for quality without breaking the passing test.

Test-first development is applicable to bug fixes and refactoring, requiring a failing test that verifies the intended behavior before you implement production code changes.

You need to write a failing test before writing production code whenever you are developing features, fixing bugs, refactoring, or changing behavior to ensure changes are validated by automated tests.

Test-driven development guides red-green-refactor cycles across modern codebases, but it requires underlying automated testing frameworks to execute tests and validate behavior changes.

Test-driven development requires minimal production code to pass tests because this discipline surfaces requirements early, reduces bugs, and ensures you only write code necessary to satisfy the validated behavior.