During the past decade, test engineers have become experts in browser compatibility testing. Just when we thought everything was under control, along come native mobile applications that need to run across platforms far more diverse than the desktop browser landscape has ever been. The variety of OSs, screen sizes, and hardware technology combine to create hundreds of configurations that need some testing. Manual testing across so many deployment targets will drive anyone crazy. Stu Stern looks at the biggest challenges in mobile testing: functional, platform, display, and device compatibility testing and explores how you can use MonkeyTalk, a free open source tool to create test suites that can be easily run across today’s menagerie of mobile devices. MonkeyTalk can help you automate functional interactive tests for native, mobile, and hybrid iOS and Android apps—everything from simple "smoke tests" to sophisticated data-driven test suites.