On the Liip blog there's a new post showing you how to set up "testing in the cloud" with the help of AWS and a Bamboo instance along with some custom configuration.
Bamboo is the continous integration service by Atlassian, the company owning the code management service Bitbucket (as well as the Jira issue tracker and Confluence wiki). Bamboo can run test suites and build any kind of artefact like generated documentation or installable packages. It integrates with Amazon Web Services, allowing to spin up EC2 instances as needed.
The article talks about the permissioning needed for the EC2 AWS instances and how to trigger automatic builds. They then get into the details of configuring the test runner and the PHPUnit setup to allow for the execution of your tests.