This module introduces the concept of Unit Testing in programming and highlights the importance of it in iOS development. It outlines how unit testing is the breaking down of code into separate components and testing each individual component to ensure each performs as designed. It also describes working with test-driven development, code refactoring, what defines a good test, the A TRIP acronym and Xcode's unit testing platform - XCTest.

This module continues to develop your knowledge of unit testing and how to implement unit testing for different functions and features. It outlines how unit testing should be used in various situations. It describes how to test asynchronous code, test endpoints, working with MVVM and work with mock data. The module also outlines what performance testing is and how to use benchmarking to highlight how a piece of software is performing.