Testing our software is an important activity during the coding phase, as well as when releasing service packs or bug fixes.

There are different levels of testing. The first level is developer testing, which often starts with the compiler or interpreter not letting us run our buggy code forcing us to test small parts of our code on the level of individual methods.

This is the first level of defense.

A second level of coding defensively is when our source code control system tells us about some conflicts to be resolved and does not let us check in our modified code.

This is very useful and absolutely necessary when we work professionally in a team of developers. The source code control system is our friend and points out changes that have been committed to a particular branch or top-of-tree either by ourselves or by our other developers, and tells us that our local version of the code is both outdated and has some conflicts that need to be resolved before we can...