Calabash-android is a cross-platform mobile automation testing tool for Android and iOS apps that allows running automated acceptance tests written in behavior-driven development (BDD) style. It uses the Cucumber framework and Ruby to write tests and interacts with the app via a test server installed on the device/emulator. Key steps include generating Cucumber feature files from templates, resigning the app, building the test server, and running tests on connected devices/emulators to tap, enter text, and validate elements using the Calabash Ruby API.