Henrik Bjørnskov's Blog: Travis & Composer sitting in a tree K-I-S-S-I-N-G
Note: This article was originally published at PHPDeveloper on 19 November 2011.
To integrate your project with travis the only thing necesarry is to have a .travis.yml file and a working PHPUnit test setup like http://github.com/simplethings/SimpleThingsFormExtraBundle. Where the Tests/vendors.php script is executed before the tests are perfomed. But it would be way cooler to just have Composer handle the autoloading and dependencies.
A sample .travis.yml file is included in the post (also here) as well as instructions for grabbing dependencies and including the autoload process in your application's bootstrap.