steipete

The Ultimate Swift Testing Playbook (2024 WWDC Edition, expanded with Apple docs from June 2025)

Updated with info from https://developer.apple.com/documentation/testing fetched via Firecrawl on June 7, 2025.

See also my blog: See also my blog post: https://steipete.me/posts/2025/migrating-700-tests-to-swift-testing

A hands-on, comprehensive guide for migrating from XCTest to Swift Testing and mastering the new framework. This playbook integrates the latest patterns and best practices from WWDC 2024 and official Apple documentation to make your tests more powerful, expressive, and maintainable.

---

1. Migration & Tooling Baseline

ole

// swift-tools-version: 6.0
// The swift-tools-version declares the minimum version of Swift required to build this package.

import PackageDescription

let package = Package(
    name: "MyPackage",
    products: [
        .library(name: "MyLibrary", targets: ["MyLibrary"]),
    ],

lukeredpath

I maintain the Community mobile app - a moderately large codebase that is fully modularized using Swift Package Manager and uses The Composable Architecture. I have recently completed the process of getting the project ready for Xcode 16 and Swift 6 and I wanted to outline the approach I took and some of the issues I encountered, especially regarding TCA.

The Approach

There are already [good

ole

#!/bin/zsh

# Test if the Swift compiler knows about a particular language feature.
#
# Usage:
#
#     swift-has-feature [--swift SWIFT_PATH] [--language-version LANGUAGE_VERSION] FEATURE
#
# The feature should be an upcoming or experimental language feature,
# such as `"StrictConcurrency"` or `"ExistentialAny"`.

thoughtpolice

## ------------------------------------------------------------------------------------------------

# Schema published automatically on the website. This allows TOML language
# servers to autocomplete and show documentation for the entries below.
#
# I use the prerelease version as my builds on my machines are often from trunk.
"$schema" = "https://jj-vcs.github.io/jj/prerelease/config-schema.json"

## ------------------------------------------------------------------------------------------------
## ---- Basic settings

tgrapperon

import Foundation
public func printStackDepth(
  label: String? = nil,
  fileID: StaticString = #fileID,
  line: UInt = #line
) {
  let thread = pthread_self()
  let stackAddress = UInt(bitPattern: pthread_get_stackaddr_np(thread))
  var used: UInt = 0
  withUnsafeMutablePointer(to: &used) {

eddy-22

A curated list of useful command line apps, in celebration of the TUI.

“Knowledge brings fear” (Mars University Mission Statement)

If you want to contribute, you are highly encouraged to do so. Please read the contribution guidelines.

ilyagr

vimdiff comes as a pre-configured merge tool for jj and can be used with jj resolve out of the box. However, the default configuration for vimdiff as a diff editor (for jj split, etc.) is barely useable.

To more conveniently use Vim as a difftool for jj, try one of the following setups:

DirDiff plugin

1. Install the DirDiff Vim plugin.

BigZaphod

//
//  PagingView.swift
//  Wallaroo - https://wallaroo.app
//
//  Created by Sean Heber (@BigZaphod) on 8/9/22.
//

import SwiftUI

// This exists because SwiftUI's paging setup is kind of broken and/or wrong out of the box right now.

jemmons

import Foundation
typealias Continuation<Ret> = (Ret) -> Void
typealias ContinuationMonad<Value> = (@escaping Continuation<Value>) -> Void
typealias Transform<T,U> = (T) -> ContinuationMonad<U>


func async<Value>(_ wrappedValue: Value) -> ContinuationMonad<Value> {
  { $0(wrappedValue) }
}