Swift Testing

This walks you through Apple's modern Swift Testing framework with the `@Test`, `#expect`, and `#require` macros instead of XCTest. It's opinionated about test structure (Arrange-Act-Assert), test double terminology (following Martin Fowler's taxonomy, not the community's loose "mock" usage), and where to put fixtures and doubles (close to models and interfaces with `#if DEBUG`, not in test targets). The decision tree is genuinely helpful for routing you to the right reference, whether you need parameterized tests, snapshot testing, or async patterns. If you're migrating from XCTest or trying to write less brittle integration tests, this gives you practical patterns worth following.