Book Image

Hands-On Design Patterns with Swift

By : Florent Vilmart, Giordano Scalzo, Sergio De Simone
Book Image

Hands-On Design Patterns with Swift

By: Florent Vilmart, Giordano Scalzo, Sergio De Simone

Overview of this book

Swift keeps gaining traction not only amongst Apple developers but also as a server-side language. This book demonstrates how to apply design patterns and best practices in real-life situations, whether that's for new or already existing projects. You’ll begin with a quick refresher on Swift, the compiler, the standard library, and the foundation, followed by the Cocoa design patterns – the ones at the core of many cocoa libraries – to follow up with the creational, structural, and behavioral patterns as defined by the GoF. You'll get acquainted with application architecture, as well as the most popular architectural design patterns, such as MVC and MVVM, and learn to use them in the context of Swift. In addition, you’ll walk through dependency injection and functional reactive programming. Special emphasis will be given to techniques to handle concurrency, including callbacks, futures and promises, and reactive programming. These techniques will help you adopt a test-driven approach to your workflow in order to use Swift Package Manager and integrate the framework into the original code base, along with Unit and UI testing. By the end of the book, you'll be able to build applications that are scalable, faster, and easier to maintain.
Table of Contents (22 chapters)
Title Page
Copyright and Credits
About Packt
Contributors
Preface
Index

The composite pattern


The composite pattern helps in writing proper abstractions when dealing with objects that appear in hierarchies; being containers and containees. For example, on a filesystem, a directory can contain files and other directories. In this case, the composite pattern would be a suitable abstraction. Each element of the filesystem can be either a container for other elements (a directory), or a terminal node (file).

In this section, we will see how to set up and implement the composite pattern to represent a series of unit tests organized in test suites.

Using the composite pattern to represent tests and suites

When writing unit tests, it's recommended to group together tests that are closely related to one other. We call a series of tests a suite, which can contain subsuites. Whole suites, subsuites, and individual tests can be run. These features makes the composite pattern very suitable for organizing the tests in suites, the suite itself being the composite.

 

First, we...