The book re-visits Regression testing in the light of Internet of Things Operating System testing. Book explores Machine Learning concepts applied to generic Regression test data. The book is for Software Engineering enthusiasts, test Architects who want to explore applying Machine Learning concepts to testing. As a case study, to demonstrate Internet of Things Operating System testing one of the Operating System is taken as case study. Regression test suites are written from scratch and re-engineered using leading test design tool. Automation of test script generation is explored. To demonstrate the Machine Learning concepts applied to testing Weka is used.