Calabash enables you to write and execute automated acceptance tests of mobile apps. It's cross-platform, supporting iOS and Android native apps. It's also open source and free, developed and maintained by Xamarin. Calabash consists of libraries that enable test code to interact programmatically with native and hybrid apps. The interaction consists of a number of end-user actions. Calabash helps automate and test any iOS or Android app, native or hybrid, from the UI level down. Xamarin provides both the automation framework as well as the device cloud, so you can enjoy perfect integration and continuous improvements to Calabash in response to customer needs. Calabash supports Cucumber which lets you express the behavior of your app using natural language that can be understood by business experts and non-technical QA staff.