test-driven-development

The Red-Green-Refactor cycle is a Test-Driven Development process where you write a failing test, implement minimal code to pass that test, and then refactor the code for better quality without changing its behavior.

To start Test-Driven Development, write a failing test that defines the expected behavior of your new feature. Next, write the minimal implementation code required to make that test pass, and finally refactor the code to improve its structure.

You should write tests before implementation code to enforce a rigorous development process that prevents bugs and reduces technical debt. This test-first methodology ensures code reliability by defining exact expected behavior before any production code is written.

Use Test-Driven Development when starting any new feature or writing new code in an agile environment. It establishes a strict development methodology that addresses the problem of untested code by defining expected behavior before implementation.

Test-Driven Development improves code quality and debugging by enforcing the Red-Green-Refactor cycle. By writing minimal code to pass strict tests and refactoring afterward, you systematically eliminate untested code paths and reduce future debugging efforts.