Unit Test as a Documentation : The Case of PureMVC

I stumble upon PureMVC while searching for lightweight MVC framework for C#. The learning experience of it is not what I call pleasant one. The official documentation (which still based on ActionScript version) use very long narratives with very specific term used throughout the documentation assuming too much that the reader already familiar with it. To make matter worse, there's no executable code to try anywhere. There's no one to blame, of course, since the site already say :

Beta - Unit tests are compiled and running in target platforms, as well as a Silverlight Demo. There isn't much documentation yet, however.

However, things are changing once I take a peek at the existing unit test. This is exactly the experience that Unit-Testing proponent refer to when they say "Unit Test as an Executable Documentation". It is truly function as a documentation for me, even better than pages-after-pages narratives. It's like a "picture worth a thousand words" experience.

By relying on the unit test I can make things work in very short time. It also make the pdfs that I've read earlier starting to makes sense (despite I still think the narratives need much work to be humanely-readable). It explain how I should use certain class and how it interact with other class and most importantly, how it can produce the expected result. I don't even to compile and run them to know that it will works, it seems quite clear that it will work (in fact, I don't even bother compile the unit test, a little work of copy and pasting already show in short time that it work in my own code).

I rarely on the other side of Unit Testing world i.e: read them to makes sense of the code. I usually read my own or the co-woker (which the codebase I share and already familiarity with). Seeing their usefuleness from the purely-reader side (since it's truly "someone-else's" code) gives me deeper perspective on how they can make a difference in understanding and using the completely new code.