iOS App CI/CD Optimization

This feature thread tracks the evolution of optimizing CI/CD for the GitHub iOS app. Initially, the focus was on reducing monolithic build and test times. This post details the significant reduction in testing time by leveraging Apple silicon (M1 macOS runners) and breaking down the test suite into independent jobs for each module. This resulted in a 60% reduction in testing time, from 38 minutes to 15 minutes, and enabled faster feedback loops for developers. The team also analyzed CI performance and divided each module's CI into two separate steps, build and test, using xcodebuild's build-without-testing and test-without-building.