Migrate One XCTest File to Swift Testing

This article provides a practical migration pattern for converting a single XCTest file to Swift Testing, emphasizing incremental adoption rather than a full rewrite. It covers key differences: XCTestCase becomes a suite, test methods become @Test functions, XCTAssert calls become #expect, required setup uses #require, and repeated cases become parameterized tests. The example uses a receipt validation test, demonstrating async success paths, throwing paths, and table-driven cases. It also notes availability requirements (Xcode 16+), mixing frameworks in the same target, and using @MainActor for main-thread APIs. The article is a technical tutorial focused on software testing in Swift.