In a post to his site Rob Allen shares a basic setup for using Circle CI with a PHP project for continuous integration. Circle CI provides the resources to build your project and perform tasks such as run unit tests or even deploy the resulting code to the production environment.

For a new client project, I've decided to use CircleCI to run my tests every time I push to GitHub. This turned out to be quite easy; this is how I did it.

He shares the contents of his .circleci/config.yml configuration file creating a Docker environment each time the build is executed, installing the required software, executing Composer install and running PHPCS and PHPUnit tests. He shares an example of the output from a build and how he hooked in Slack to receive notifications when the builds were complete (and pass/fail status).