Read about phpRack in php|Architect June 2010: "Integration Testing with phpRack Framework". phpRack is a light framework for automation of integration tests. By integration tests we mean software modules that should be executed in the production environment, in order to validate that said environment is configured as expected. For example your product is a web2.0 application which depends on proper configuration of PHP, Apache, MySQL and availability of YouTube, Flickr and GoogleMaps API's. Your product is properly tested with unit tests (obviously you're using stubs for said services and components). When the product is deployed to the production environment, you want to be sure that the services you need are configured and available. If they are not — you want to get a notification about it before your end-users. And you want to get a detailed notification.