Testing your UI with Apple’s UI testing framework is great for creating tests that can be used across a variety of different devices and iOS versions however those tests can sometimes be slow, and occasionally just stop working.
Snapshots provide a nice alternative to Xcode’s UI tests and Facebook’s FBSNapshotTestCase library provides a nice framework for performing Snapshot UI tests.
Dominik Hauser has written a nice step-by-step guide to configuring and using FBSnapshotTestCase showing how to
You can find the tutorial on the Swift and Painless blog.
You can find FBSnapshotTest on Github here.
A nice straightforward guide on using FBSnapshotTestCase.