test-driven-development

The red-green-refactor workflow in test-driven development involves writing a failing test, implementing minimal production code to pass that test, then refactoring for clarity and robustness. This cycle ensures code meets requirements precisely while maintaining testable design.

To start writing tests before production code, write a failing unit test that captures the intended behavior of your new feature. Then create the minimal code required to make that test pass, ensuring early failure discovery before any production changes.

Test-driven development supports refactoring by providing a safety net of existing tests. After implementing minimal code to pass tests, you refactor with confidence knowing that any regression or misalignment with requirements will immediately surface as a test failure.

A test-first workflow forces failures to guide implementation and design, capturing misalignment with requirements before any production changes. This prevents wasted work, reduces defects, and promotes modular, testable interfaces that are easier to evolve and maintain.

TDD can be applied across software projects for both feature development and bug fixes. By writing a failing test that reproduces the bug or defines the feature first, you ensure code does exactly what is intended before implementing the minimal production fix.

A test-first approach may not suit exploratory prototyping where requirements are undefined, because TDD requires writing real tests for intended behavior before production code exists. It is most effective when desired outcomes can be specified upfront to guide design.