What Is TDD, and Why Should You Start Today?

The Red-Green-Refactor Cycle

Test-Driven Development (TDD) means writing a failing test first (Red), then writing the minimum code needed to make it pass (Green), and finally improving the code without changing its behavior (Refactor).

Why This Backwards-Seeming Approach Works

At first glance, writing tests before code seems slower. In practice, TDD forces you to think precisely about what needs to be built before you build it — which prevents writing extra, unnecessary code.

The Hidden Benefit: Living Documentation

A TDD test suite doubles as living documentation. Any new developer can read the tests to understand exactly what each part of the system is supposed to do — no separate docs that inevitably go stale.

Start Small

You don't need to TDD your entire project from day one. Start with one small, self-contained feature. Once you feel the difference in confidence when changing code later, you'll naturally reach for this approach more often.