Move Fast and Break Nothing
Comparing the results of requests processed against both the new and old system is a pattern. <a href="http://www.alwaysagileconsulting.com/application-pattern-verify-branch-by-abstraction/" rel="nofollow">http://www.alwaysagileconsulting.com/application-pattern-ver...</a><p>It was also done in mainframes at the processor instruction level.