# Legacy code

> > "They're writing legacy code, man." …

> "They're writing legacy code, man." …
>
> To me, legacy code is simply code without [tests](https://wiki.g15e.com/pages/Unit%20test.txt). I've gotten some grief for this definition. What do tests have to do with whether code is bad? To me, the answer is straightforward, and it is a point that I elaborate throughout the book. Code without tests is bad code. It doesn't matter how well written it is; it doesn't matter how pretty or object-oriented or well-encapsulated it is. With tests, we can change the behavior of our code quickly and verifiably. Without them, we really don't know if our code is getting better or worse. --pxvi, <Working effectively with legacy code>