Software testing, documentation

I made some plugin for JUnit and now I need to write documentation. I need help with introduction. There are several things that I need to mention, and shortly explain before writing about plugin. These things are:

• Mention why software testing is important (TDD (test driven development), refactoring, adding new parts of code, teamwork, automation, code coverage...)
• other things about my plugin, but this I have to write alone :)

Ok so, if someone has some literature or links it would be helpful. Thanks