test-driven-development

Test-driven development improves code quality by enforcing a failing test before implementation, ensuring your code reliably meets behavioral requirements through the red-green-refactor cycle.

The red-green-refactor cycle in unit testing is a workflow where you write a failing test, implement minimal code to pass it, then refactor to improve structure while keeping all tests green.

To start writing tests first for a new software feature, create a failing unit test that captures the desired behavior, implement the minimal code to make it pass, then refactor with confidence.

You do not need a specific test runner to use test-driven development. It works across standard software projects using common testing frameworks, requiring only a basic node/npm project setup.

You can use test-driven development for bug fixes and refactoring by writing a failing test that reproduces the bug or verifies the new structure before changing the implementation code.

You should avoid a tests-first approach for exploratory prototyping where behavior is undefined, as test-driven development enforces specifying expected behavior through a failing test before writing any implementation code.