Jest is a fantastic testing library, but maybe you've been putting off the switch because migrating all of your existing tests from another library seems like a daunting task. With jest-codemods, you can automate most, if not all, of that migration! The jest-codemods CLI is a wrapper around jscodeshift that is specifically focused on helping you migrate from several popular test runner and assertion library combinations to Jest. In this lesson, we'll walk through converting a small sampling of tests created with Mocha, Sinon and Chai over to Jest. We'll even take a look at a couple edge cases where the conversion requires some manual intervention so you can be prepared for those in your own project.