http://david.heinemeierhansson.com/2012/emails-are-views.html
In this article, DHH talks about the same incidental-duplication that Avdi talks about.
blog-post-emails-are-views#trade-off-system-simplicity-for-easy-mocking1 DHH: "the simplicity of the system is downgraded in order to ease the job of mocking. Terrible idea." blog-post-emails-are-views#trade-off-system-simplicity-for-easy-mocking1