Another common misconception is that unit tests can be written in the last three months of the project. Unfortunately, without the unit tests development drags on and eats up those last three months and then some. Even if the time is available good unit test suites take time to evolve. Discovering all the problems that can occur takes time. In order to have a complete unit test suite when you need it you must begin creating the tests today when you don't.
Unit tests enable collective code ownership.
When you create unit tests you guard your functionality from being accidentally harmed. Requiring all code to pass all unit tests before it can be released ensures all functionality always works. Code ownership is not required if all classes are guarded by unit tests. Copyright 1999 J. Donovan Wells all rights reserved.