14 · Shipping & Collaboration
Unit Test
An automated check on one piece of code
A small automated test that confirms one bit of code does what it should, run constantly to catch anything that breaks it.
Concrete example
A test asserts that adding 2 and 2 returns 4; if a change breaks that, you know at once.
Why it matters
What lets AI write code safely — the tests, not your faith, tell you it actually works.