Test in production

Unit tests and staging environments are nice and all but how do you know whether your latest release works? SaaS vendors must test in production. Consider your users to be testers, or, better: create test users and run nonstop tests in production deliberately. As this article says:

“Certain services need to know that an account isn't real, so we don't count or bill users like production accounts or match them with a production user. With these cases handled, all other services essentially treat all accounts, production or test, exactly the same.”