If you're looking at doing screenshot testing (android-screenshot-tests, Karumi/Shot, ios-snapshot-testing, swift-snapshot-tests etc.), I would love for you to take a look at this project and set it up as part of your development workflow. I'm happy to provide OSS support on GitHub. I want to make it a self-sustaining OSS project.
(PS. I'm also the original author of android-screenshot-tests, which is now the de-facto library for screenshot testing on Android, and that's how I got into this space)