Create a specific config for 'testing' environment

I've experienced some problems when I was applying your solution to my current CodeIgniter project.

I figured out that the problem was related to my config/autoload.php and the main controller of my project.

I solved this creating exclusive <a href="http://ellislab.com/codeigniter/user-guide/libraries/config.html">config for the testing environment</a>, using an clean autoload.php file and changing the default controller on routes.php

So, I think is a good idea to use an exclusive, clean config for the testing environment. What do you think?