Time is our most precious resource, as both humans and programmers. An 8-hour workday contains 480 minutes. Out of the box, running a new iOS app's test suite from the terminal using xcodebuild test takes over 25 seconds on my M4 MacBook Pro. After extracting my application code into a Swift package—such that the application project itself contains virtually no code at all—running swift test against the same test suite now takes as little as 0.4 seconds. That's over 60 times faster. Given 480 minutes, that's the difference between having a theoretical upper bound of 1152 potential actions per day and having 72,000. If that number doesn't immediately mean anything to you, you're not alone. I've been harping on the importance of tightening this particular feedback loop my entire career. If you want to see the same point made with more charts and zeal, here's me saying the same shit a decade ago (https://www.youtube.com/watch?v=jmPcVTHmdVo&t=1912s): https://www.youtube.com/embed/jmPcVTHmdVo?start=1912 And yes, it's true that if you run tests through the Xcode GUI it's faster, but (1) that's no way to live, (2) it's still pretty damn slow, and (3) in a world where Claude Code exists and I want to constrain its shenanigans by running my tests in a hook (/posts/tldr-is-the-best-test-runner-for-claude-code), a 25 second turnaround time from the CLI is unacceptably slow. Anyway, here's how I did it, so you can too.