Testing an application that lives in the cloud requires the same tricks and techniques as one that resides on your own iron. But when testing something that is going to live in the cloud, you need to test not just the user-facing functionality, but all the things that make it "cloud". In fact, it could be argued that the ensuring the cloud-ness of your application is almost more important than the user-facing part as re-architecting for the cloud problems will absolutely cause re-testing.
In the illustrious tradition of heuristics and mnemonics, Adam proposes that we add "C0MEDIES" to our vocabulary when testing an app that runs on a cloud-like environment. By dealing with the "C0MEDIES", you can manage the Chaos of the cloud, while doing 0 downtime deploys, for applications that at Monitored, are Elastic, in an infrastructure that is constantly being Developed, is Idempotent, Efficient and Secure.