NetTuts.com has kicked off a new series of posts today that answers the question "Why unit test?" The series, Unit Testing Succinctly aims to define what unit testing is, approaches to implementing them and what they can do to help you and your application.

The usual mantra we hear regarding any software methodology is that it improves usability and quality, reduces development and testing time, and brings the product to market faster and with fewer bugs. These are lofty goals, but I have yet to see a methodology deliver the Grail of software development. Ultimately, the primary reason to write unit tests is to prove correctness, and this happens only if you write unit tests well.

In this first post they cover three of the more general reasons for making the dive into unit testing your applications at all. These are more "business value" kinds of ideas but they trickle down into the development level, providing value for the developers too.

• Measuring Correctness
• Repetition, Repetition, Repetition
• Code Coverage

Their main point to reinforce is the first of the three, though. Unit testing helps to measure and ensure correctness of both the code itself and the functionality it performs.