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)

UI tests

We have written one UI test in Chapter 6, Putting It All Together, to implement a functional test for the input of new to-do items. But, the other features of the UI aren't tested yet. Unit tests can test whether an element is on the screen, but doing this is cumbersome. It is much easier to use the new UI tests that were introduced in Xcode 7.

As you may have already noticed, UI tests are slow. They need to start the app and wait until the UI is loaded before they can interact with it. In addition to this, the app is closed and reopened after each test to make sure that each test starts with a defined state. As a result, you should not test each UI element in isolation. You'd rather write tests for a complete function of the app (for example, adding a to-do item to the list).

In the case of the ToDo app implemented in this book, a useful UI test would test...