This book covers a pragmatic approach to writing well tested code. It is aimed at the software practitioner who writes code on a daily basis and has to contend with issues arising with large untested legacy code bases. Basic principles of test-driven development (TDD) are introduced, such as Test First, Red-Green-Refactor, Remove Duplicate code, Dependency Injection, and Single Responsibility. Approaches covered include TDD, behavior-driven development (BDD), UI, and acceptance testing with common standard/open source frameworks. Practical examples are provided on how to practice Test-Driven Development and acceptance testing in Swift. Helpful instruction will teach iOS developers to retrospectively fit tests to legacy code, refactor legacy code so as to make the code more testable, install and configure a popular Swift BDD framework, practice BDD with Xcode, and create automated UI tests with Xcode. Additionally, many projects have legacy code bases. Legacy code is often seen as a blocker when it comes to implementing any kind of testing. This book provides techniques that can be used to retrofit tests to legacy code bases. What You Will Learn:Designing with test-driven development techniquesFitting test to legacy code retrospectivelyRefactoring legacy code to make the code more testableInstalling and configuring popular Swift BDD frameworksPracticing BDD with XcodeCreating automated UI tests with XcodeWho This Book Is For:Primary audience are Swift developers. Secondary audience would be mobile app testers.