We are working on the written documentation that will accompany the code. We plan on an entire chapter around testing with sections around unit testing. It is still evolving at this point, but look for a draft within the next few weeks.
General unit testing is covered in a lot of books that are available. A few titles I read when I was learning are:
- Test Driven Development: By Example by Kent Beck
- Test-Driven Development in Microsoft .NET (Microsoft Professional) by James W. Newkirk and Alexei A. Vorontsov
There are newer books available, but I have not read in this particular space in a while, and the above were able to get me up and running.
We have a mixed team of developers. Some prefer doing test-first. Others do test-after. Different portions of the code were done each way, depending on who worked on it. Personally, I much prefer the test-first approach.
Let me know if that helps,