Making Automated Testing of Cloud Applications an Integral Component of PaaS

Traditional testing is inadequate for the complexity of modern cloud application software stacks. While the platform-as-a-service (PaaS) model has streamlined application development and deployment, its multiple abstraction layers and dependencies have made testing more difficult. We argue that a modern PaaS offering should include a facility to thoroughly and automatically test a deployed cloud application with only little developer effort. To support this vision, we propose layered parameterized tests (LPTs) -- generalized integration tests suitable for cloud applications with multiple processing layers. From LPTs, a testing facility automatically generates concrete tests using layered symbolic execution, which focuses on exercising developer-written application logic instead of PaaS library code. We present our design of an automated testing system built on these concepts and demonstrate its use for a modern PaaS.