This is a very basic Split Testing implemented in Swift. You can use A/B Testing and "A/B/C" testing. You can also have a weighted distribution for the A/B testing. SwiftABTest will save the split group membership of a user into NSUserDefaults to guarantee this specific user always gets the same result until an app update.
Just use CTSplitTest().runABTest(...) - it uses a 50-50 weighted distribution by default but you can adjust it by using CTSplitTest.runABTest([0.3,0.7],...) to have a 30-70 weighted distribution.
You need to implement the measurement of the split testing yourself in the different group closures. You also need to send a new update to Apple if you want to change the implementation of the A/B test.
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Feel free to provide a PR with new features or leave an issue if you have troubles!