How do you test iOS apps with XCTest?

1 What is XCTest?

XCTest is a framework that provides a set of tools and APIs for testing iOS, macOS, watchOS, and tvOS apps. It allows developers to write tests in Swift or Objective-C, and integrates with Xcode, the IDE for iOS development. XCTest supports various types of tests such as unit tests, UI tests, performance tests, and snapshot tests. Unit tests verify the behavior and logic of individual components or classes in an app. UI tests simulate user interactions with an app's interface. Performance tests measure the speed and efficiency of an app's code. Lastly, snapshot tests compare the visual output of an app's UI with a reference image. All these tests help developers ensure the accuracy and consistency of their apps' UI across different devices, orientations, and configurations.

2 How to create tests with XCTest?

To create tests with XCTest, you need to add a test target to your Xcode project. This bundle of test files associated with your app target contains your test classes and methods. You can add a test target by selecting your project in the Xcode navigator and clicking on the + button under the Targets section. Depending on the type of tests you want to write, you can choose from different templates, such as an iOS Unit Testing Bundle, an iOS UI Testing Bundle, or an iOS Performance Testing Bundle. For example, if you choose the iOS Unit Testing Bundle, it includes a test case class that inherits from XCTestCase and allows you to write unit test methods using the XCTAssert family of functions. Similarly, the iOS UI Testing Bundle includes a test case class that inherits from XCTestCase and allows you to write UI test methods using the XCUIApplication and XCUIElement classes. Lastly, the iOS Performance Testing Bundle includes a test case class that inherits from XCTestCase and allows you to write performance tests using the measure family of functions.

3 How to run tests with XCTest?

To run tests with XCTest, you can use the Xcode's Test navigator, which shows you all the test targets, classes, and methods in your project. You can run all the tests in a target, class, or method by clicking on the play button next to it, or by using the keyboard shortcut Command + U. You can also run a specific test by right-clicking on it and selecting Run. Xcode will show you the results of your tests in the Test navigator, as well as in the editor and the debug area. You can see the status, duration, and output of each test, as well as any failures, errors, or warnings. You can also use the Xcode's Report navigator to view the history and details of your test runs.

4 How to debug tests with XCTest?

To debug tests with XCTest, you can use the Xcode's debug tools, such as breakpoints, console, and variables view. You can set breakpoints in your test code or your app code, and Xcode will pause the execution of your tests when they are hit. You can then inspect the state of your app and your tests, using the console and the variables view. You can also use the debug commands, such as step over, step into, or continue, to control the flow of your tests. You can also use the Xcode's Test Failure Issues navigator to see the location and reason of your test failures, and jump to the corresponding code.

5 How to write better tests with XCTest?

Writing better tests with XCTest requires following some best practices and tips. Use descriptive and consistent names for test targets, classes, and methods to easily identify and organize your tests. SetUp and tearDown methods help to initialize and clean up any resources or state shared by test methods, such as mock objects, databases, or files. Test-specific subclasses or extensions add custom functionality or helpers to test classes. Test fixtures and data providers create and reuse common data sets or scenarios for tests. Test doubles such as stubs, mocks, or fakes isolate and control the dependencies or interactions of app's code. Code coverage and test reports measure the quality and coverage of tests to identify any issues in tests or app's code.

6 Here’s what else to consider

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