Test Early. Test Often. Test Automatically.

Tip 62: Test Early. Test Often. Test Automatically.

Tip 63: Coding Ain't Done 'Til All the Tests Run.

The earlier a bug is found, the cheaper it is to remedy.

a good project may well have more test code than production code. The time it takes to produce the test code is worth the effort.

- Andrew Hunt, David Thomas (2000), The Pragmatic Programmer (p.237-238),
Addison-Wesley Professional