Write Once, Test Everywhere: Cross-Platform Testing for React Native

Testing React Native apps has always been a trade-off between speed and realism. Jest is fast, familiar, and excellent for unit tests, but it runs in Node.js and relies on mocks for native modules. End-to-end frameworks offer realism, but at the cost of complex setup, ongoing maintenance, and slower pipelines. Enter React Native Harness, a new testing framework that lets you run Jest-style tests directly on real devices and simulators, with full access to native modules and no mocks by default.