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This week with Swift Testing starts with checking how test disabling differs from XCTest. In XCTest, Xcode identifies a function as a test only if its name starts with the “test” prefix, so putting e.g. “disabled” instead makes the test inactive. Swift Testing simplifies that approach by introducing the @Test macro with a .disabled trait that you can pass as an argument. What’s the benefit? You no longer need to modify each test name to disable it. What’s more, you can include context directly within the trait to justify why the test is disabled. ...

What is macro? 💡 Macro is a feature that generates code during compilation. Unlike macros in C, which work like “find and replace”, Swift macros are type-safe and context aware, making them powerful tools reducing boilerplate code. Two types of macros attached - use @ prefix, tied to a declaration adding extra logic to it, like: @Test, @Model, @Observable freestanding - use # prefix, standalone code that can be invoked independently as a part of the code, like #expect, #Predicate, #warning Example of attached macro ⤵️ ...

Optionals are a core of Swift - we deal with them daily, both in production and testing code. Whether you write tests with XCTest or Swift Testing, unwrapping optionals is a common case. In XCTest there is XCTUnwrap operator. Swift Testing introduces #require macro. Is there any difference between them? Not really! Both require the test function to handle exceptions and try keyword before. Gif ⤵️ Code ⤵️ XCTest ...

Swift code refactor in action 👨🏻‍💻 Common scenario: formatting user profile name - I bet any of you faced this kind of task. At first glance, it look straightforward, but when you take a closer look, you’ll notice two potential improvements: 1️⃣ One single return - simplification of the function flow. 2️⃣ Centralised formatting logic - reduces the chance of bugs. Check out the animated gif and the code where I refactor to address these issues. ...

Today we check how testing error has changed in the new framework. In XCTest, we use XCTAssertThrowsError to check if a specific error is thrown. This assertion comes with the error handler closure where we can perform additional checks like e.g. verifying the exact error type. With Swift Testing, this process is even simpler, especially when an error conforms to Equatable. We can directly specify the expected error in the expect macro and it automatically checks the type. ...