Juan Treminio has posted the latest part of his unit testing series to his site today - the fifth part that looks at using mock methods on mock objects and overriding constructors.
Previously in my PHPUnit tutorial series, you learned about the very powerful concept of mock objects and stub methods. This concept is central to successful unit testing, and once it fully 'clicks' in your head you will start to realize how useful and simple testing can be. There is also another thing I want to make clear: creating tests is basically a puzzle - you simply have to go step by step, making sure all the pieces fit together correctly so you can get your green. I hope to make clear what I mean by the end of this tutorial.
He assumes you already know about mock objects and introduces the concept of "stub methods" and "mock methods", noting the difference between them. He then gets into what he calls the "four pathways of getMockBuilder" and talks about the rationale behind mocking methods in the first place. He then gets into constructors and how you can work around the "bad" ones with help from mock object functionality.
If you're interested in reading the rest of the series, you can find links to them here.