There are probably quite a few typos here yet as I just knocked this out, but this is derived from my talk to the New York Continuous Delivery Meetup* last week about achieving Continous Delivery workflows.
http://docs.ansible.com/test_strategies.html
(Spelling updates and improvements to docs crosslinking are always welcome. To contribute, just hit the github link in the upper right)
The purpose here is mostly to talk about a few modules that are particularly good for testing, as well as appropriate attach points to build in safeguards into a deploy or update process.
–Michael