Testing Swift (iOS/macOS) Applications: From Unit Tests to UI Automation

Testing is one of the most underestimated yet critically important parts of iOS and macOS development. This book bridges the gap between basic Swift knowledge and a professional level where your code is covered by tests and releases happen without the fear of "breaking something." You will learn not just to write tests, but to build a reliable quality assurance system.

Who this book is for

• iOS/macOS developers who already know how to write in Swift but want to learn testing from scratch or systematize their knowledge.
• Team Leads and Technical Managers who are implementing a testing culture in their team and looking for practical approaches.
• Junior and Middle developers striving to reach the next level — the ability to write tests is often a deciding factor in hiring.
• Developers on other platforms who are transitioning to Swift and want to incorporate testing into the architecture from the start.

What you will learn

• XCTest basics — writing and organizing unit tests, assertions, test suites.
• Mocking and Stubbing — isolating code from external dependencies (network, database, file system).
• UI testing with XCUITest — recording and writing tests for the user interface, handling asynchronous states.
• Testing Combine and async/await — verifying reactive code and modern asynchronous patterns.
• Integration testing — testing Core Data, network requests, and Keychain.
• Performance testing — measuring performance and identifying bottlenecks.
• CI/CD for tests — setting up GitHub Actions, Bitrise, Xcode Cloud for automatic test execution.
• Code coverage and TDD — how to measure coverage and write tests before code (Test-Driven Development).

Why this book

Unlike scattered articles and Apple documentation, this book presents a unified approach: from project setup to complex scenarios like testing multithreading or SwiftUI. Each chapter contains real code examples that you can apply immediately. You will get not just theory, but ready-made templates and best practices proven in commercial projects.

The book is written in a lively style with a focus on practice. After reading it, you will be able to confidently answer testing questions in interviews and, most importantly, write stable applications that don't let users down.