Where to place common library for unit test functions in Cakephp?

Currently several of my unit tests need common functions such as logging in a specific user fro开发者_StackOverflowm the mock objects or making sure that no one is logged in. I currently have those functions in a file which I include via a regular old include statement. That doesn't seem very cakey to me. I also don't want to keep typing the include statement at every test, so I'd like to do it a high level and have it available to all my tests and do so, of course, without modifying the core cakephp files.

So I'm left looking for a place to put the mustbeLoggedIn('usertype'); -type functions that will help keep my testing DRY, but fit better in the objects. So far I havent been successful extending the test object via the usual behaviors, helpers, or vendors that cake uses. Any best practices?

---

/app/app_controller.php