Battle.net is the online service that runs Blizzard’s games. As such, it is a large scale distributed system with many interacting parts and dependencies on various services and data. While developing Battle.net servers, I needed a way to isolate and test functionality that I was working on.
This talk covers my experience designing for testability of components in a distributed system, and practical ways to structure classes and data to facilitate testing. I will also present my solution to the problem of testing my code for correctness, performance and scalability without having to deploy a full-scale environment and spin up a million clients.