Agent Skills: xctest-patterns

Expert XCTest decisions for iOS/tvOS: test type selection trade-offs, mock vs stub vs spy judgment calls, async testing pitfalls, and coverage threshold calibration. Use when designing test strategy, debugging flaky tests, or deciding what to test. Trigger keywords: XCTest, unit test, integration test, UI test, mock, stub, spy, async test, expectation, test coverage, XCUITest, TDD, test pyramid