test-driven-development

Test-driven development is a practice where you write failing tests to define expected behavior before coding. The red-green-refactor cycle means writing a failing test, implementing minimal code to pass it, then refactoring for clarity and safer design.

Start writing unit tests before production code by creating a failing test that specifies the intended behavior of your new feature. Next, implement the minimal code required to make that test pass, and finally refactor the code for clarity.

You need an automated test framework to enforce test-driven development practices, but no specific one is required. The workflow relies on your existing testing framework to run unit tests and verify that production code meets defined behavior.

Test-driven development works for bug fixes and refactoring existing code. By writing tests that define expected behavior before changing code, you catch regressions early and enable safer refactoring with concrete feedback on design decisions.

Writing failing tests first reduces risk by ensuring tests define expected behavior before implementation. This approach guides design decisions with concrete feedback and enables early bug detection, catching regressions before they reach production.