Hi, my name is Donny

When you turn on strict concurrency checking or you start using the Swift 6 language mode, there will be situations where you run into an error that looks a little bit like the following: Main actor-isolated property can not be referenced from a Sendable closure What this error tells us is that we're trying to use something that we're only supposed to use on or from the main actor inside of a closure that's supposed to run pretty much anywhere....

When Apple released Xcode 16 last year, they made the Swift 6 compiler available along with it. This means that we can create new projects using Swift 6 and its compile-time data race protections. However, the big question for many developers is: Is 2025 the right time to adopt Swift 6 fully, or should we stick with Swift 5 for now? In this post, I won’t give you a definitive answer. Instead, I’ll share my perspective and reasoning to help...

With Swift 6, we have an entirely new version of the language that has all kinds of data race protections built-in. Most of these protections were around with Swift 5 in one way or another and in Swift 6 they've refined, updated, improved, and expanded these features, making them mandatory. So in Swift 5 you could get away with certain things where in Swift 6 these are now compiler errors. Swift 6 also introduces a bunch of new features, one...

Unit tests should be as free of external dependencies as possible. This means that you want to have full control over everything that happens in your tests. For example, if you're working with a database, you want the database to be empty or in some predefined state before your test starts. You operate on the database during your test and after your test the database can be thrown away. By making your tests not depend on external state, you make...

Swift's new modern testing framework is entirely driven by asynchronous code. This means that all of our test functions are async and that we have to make sure that we perform all of our assertions “synchronously”. This also means that completion handler-based code is not as straightforward to test as code that leverages structured concurrency. In this post, we’ll explore two approaches that can be useful when you’re testing code that uses callbacks or completion handlers in Swift Testing. First,...

In a previous post, I wrote about using the #expect macro to ensure that certain assertions you want to make about your code are true. We looked at testing boolean conditions as well as errors. In this post, I would like to take a look at a macro that goes hand-in-hand with #expect and that is the #require macro. The #require macro is used to ensure that certain conditions in your test are met, and to abort your test if...