I put together a TDD screencast this week after having the same conversation more than once. It boils down to the topic of whether people can actually write their unit tests before writing their code. With this screencast, I wanted to illustrate that it's not only possible, but that it's also highly productive (once you get the tooling right).
This is not an introduction to TDD, nor an introduction to domain modeling, DDD, or any other high level concept.
If you want more information on the techniques used in this screencast, I will direct you to the following resources:
- The Domain Model Pattern
- Very Brief Writeup on Martin Fowler's Blinki (I recommend you add his feed to your RSS reader)
- A longer description can be found in his book, Patterns of Enterprise Application Architecture, along with complementary and alternative architecture patterns. PoEAA is the authoritative book on a multitude of architecture patterns as found in the wild.
- A highly recommended methodology on building domain model applications can be found in Eric Evans book, Domain Driven Design (also lovingly refered to as DDD). I highly recommend it as well.
- Test Driven Development
- Object-Oriented Programming
- This is the foundation for everything else. If you can't name at least three principles of object-orientation (and I'm not talking about "polymorphism", "encapsultation", etc), then I recommend brushing up on them.
- Robert Martin does a good job laying them out in Agile Principles, Patterns, and Practices in C#
- For advanced learning, people tend to go with one of the Head First books or Craig Larman's book. I've mostly seen people practicing Responsibility-Driven Design (within the context of TDD/DDD) in the wild.
You can download both the screencast (Windows Media - 50 MB) and sourcecode here.
The tools used in this screencast include ReSharper, MbUnit, and Test Driven.NET.
I'll try and get another screencast up soon which shows building domain services, the service layer, and data access (ie.. putting the domain model to work).
Please feel free to email me if you have questions/flames/comments on this in the mean time. My email address is evan@thisdomain.com.
