Test Driven Development for Embedded C

The TDD Microcycle

I’ll start by telling you what TDD is not. It is not spending an hour, a day, or a week writing masses of test code, followed by writing reams of production code.

TDD is writing one small test, followed by writing just enough production code to make that one test pass, while breaking no existing test. TDD makes you decide what you want before you build it. It provides feedback that everything is working to your current expectations.

At the core of TDD is a repeating cycle of small steps known as the TDD microcycle. Each pass through the cycle provides feedback answering the question, does the new and old code behave as expected? The feedback feels good. Progress is concrete. Progress is measurable. Mistakes are obvious. ...