During a recent project, I encountered problems with the flash messenger not playing ball with PHPUnit. The problem, the FlashMessenger using a session namespace, and trying to start the session. Additionally to this problem, how do you test that the flash message is set as you'd expect (or not as the case may be). The answer to both of these problems, lies in the same solution. a Mock Object.

He includes the code to mock out the FlashMessenger component and expose the "addMessage" method. In his first test, the assertion is that this method is never called (failure if it is) and in the second, it should only be called once.