Book Image

Test-Driven iOS Development with Swift 4 - Third Edition

By : Dr. Dominik Hauser
Book Image

Test-Driven iOS Development with Swift 4 - Third Edition

By: Dr. Dominik Hauser

Overview of this book

Test-driven development (TDD) is a proven way to find software bugs early. Writing tests before you code improves the structure and maintainability of your apps. Using TDD, in combination with Swift 4's improved syntax, means there is no longer any excuse for writing bad code. This book will help you understand the process of TDD and how to apply it to your apps written in Swift. Through practical, real-world examples, you’ll learn how to implement TDD in context. You will begin with an overview of the TDD workflow and then delve into unit-testing concepts and code cycles. You will also plan and structure your test-driven iOS app, and write tests to drive the development of view controllers and helper classes. Next, you’ll learn how to write tests for network code and explore how the test-driven approach—in combination with stubs—helps you write network code even before the backend component is finished. Finally, the book will guide you through the next steps to becoming a testing expert by discussing integration tests, Behavior Driven Development (BDD), open source testing frameworks, and UI Tests (introduced in Xcode 9).
Table of Contents (9 chapters)

Generating mocks with Sourcery

In this book, you created all the needed mocks yourself. You may have noticed that this is a boring task. Most mock classes consisted of mainly boilerplate code. Fortunately, there is a solution: Sourcery ( From its GitHub page:

"Sourcery scans your source code, applies your personal templates, and generates Swift code for you, allowing you to use meta-programming techniques to save time and decrease potential mistakes."

There are many templates for common tasks that are ready to use. For example, there is a template to generate mock classes from protocols. Let's have a look how we could use Sourcery to generate a mock for ItemCell.

To enable Sourcery to generate the code, we need to add a protocol with the methods that should be mocked. Imagine, we want to generate a mock for the method...