MVP Tutorial for Beginner

What are some good resources for learning more about this design pattern, including how to implement effective unit tests for it?

These resources should offer sample code snippets, preferably in Python though not necessarily. Further, aside from the code snippets the resources should also offer some detailed explanations regarding what MVP is, why it is used, why it is effective, and when not to use it.

Finally, the resources should not assume a professional or university level of training. It's ok if they assume you have a firm understanding of basic, and even 'above basic' programming principles.