GTAC 2015: Hands Off Regression Testing

http://g.co/gtac Slides: https://docs.google.com/presentation/d/1KITWbK46rm-lDZce_SqxegHTPjc9Ez-broxDTpfBpK8/pub Karin Lundberg (Twitter) and Puneet Khanduri (Twitter) Your team has just finished a major refactor of a service and all your unit and integration tests pass. Nice work! But you’re not done just yet. Now you need to make extra sure that you didn’t break anything and that there aren’t any lurking bugs that you haven’t caught yet. It’s time to put Diffy to work. Unlike tools that ensure that your code is sound, like unit or integration tests, Diffy compares the behavior of your modified service by standing up instances of your new service and your old service side by side, routing example requests to each, comparing the responses, and provides back any regressions that have surfaced from those comparisons. Also, we've just open sourced the tool and it is quickly becoming one of the most popular among Twitter's open source projects.