What is Swift UI and How to Test it?

Apple Inc. announced the SwiftUI framework in 2019, which can be used to develop apps for iOS, macOS, tvOS, and watchOS. For creating innovative user interfaces for Apple’s iPhone, iPad, and Watch, this has been the best option.

Using this UI makes coding a breeze and feels more natural. For quite some time, programmers have been at a loss as to whether or not they should use storyboards or construct the UI of an application programmatically. SwiftUI’s introduction has been a great help in resolving ambiguity.

Before SwiftUI, Xcode’s storyboards and interface builders were the only options for creating iOS apps. They’d move things about on the screen and then connect those movements to the source code.  However, today’s cross-platform SwiftUI gives a way to build applications with less code if you wish to design a user interface.

What is Swift UI?

SwiftUI is a programming language that allows you to design unique applications using Swift. Although SwiftUI is a new framework, it doesn’t feel that different to a developer who is already familiar with Swift programming via AppKit and UIKit.

SwiftUI empowers you to make appealing apps for all Apple platforms using the full potential of Swift and unexpectedly little code. You may enhance the user experience for all Apple devices by using a standard set of tools and application programming interfaces (APIs).

SwiftUI was released alongside iOS 13 by Apple in 2019. You can think of it as a user interface toolkit since it facilitates declarative application development. It simplifies the process of creating applications for all Apple platforms with minimal coding. Have a look at some of the most useful components of the SwiftUI framework pertaining to UI test Swift: 

• List views, enhanced search capabilities, and many other features are available. 
• New Rotor API that speeds up user interactions by highlighting the most crucial screen elements in a simple list. 
• With the Always-On Retina Display feature, your watchOS apps will continue to be visible even when you switch the watch face off. 
• Translation into an iOS-compatible graphical user interface element is handled automatically. 
• Design, develop, and test your app’s user interface in real-time with Xcode’s live preview.
• After introducing each framework independently, it is time to compare them and discover their differences.

When to use SwiftUI?

• Creating new features for use within an app is reportedly the quickest when done with SwiftUI. You can get almost the same results in considerably less time, and it involves a lot less code. The live preview functionality in SwiftUI is another factor that expedites app creation. This is why the adoption of Swift Chat SDK among iOS app developers is anticipated with such enthusiasm. 
• If you’re looking for a framework to help you create outstanding transitions and animations, look no further than SwiftUI. There is a tonne of free animations available to use for developers. In addition, SwiftUI makes it simpler to switch between views.
• SwiftUI’s claimed compatibility with Apple’s mobile devices (such as the Apple Watch, iPhone, and MacBook) is a major selling point. The views in SwiftUI should scale to fit any device.
• If you want to make iOS widgets, SwiftUI is the way to go. SwiftUI and widgets make a great pair. Your developers will have to write some SwiftUI code if the app needs a widget. 

Benefits of SwiftUI 

• As a result of being more clear and more succinct, SwiftUI code is more readable and manageable. Instead of writing large chunks of imperative code, you can construct your UI with SwiftUI using simple statements that describe what you want to accomplish.
• UI testing in Swift with improved support for live previews speeds up the design and development process. SwiftUI lets you preview your UI across different devices and orientations simultaneously while you work, so you can see your changes as you make them.
• More complex features may be built with fewer effort thanks to SwiftUI’s superior compatibility with other frameworks like Combine and RealityKit. Without having to deal with the intricacy of UIKit, SwiftUI allows you to use these frameworks to construct features like reactive programming, asynchronous processes, and augmented reality.
• Apps that are both accessible and localized for a variety of languages and areas are made easier with SwiftUI’s enhanced support for accessibility and localization. By incorporating native support for dynamic type, accessibility labeling, and localization, SwiftUI facilitates the development of apps that are both linguistically and culturally inclusive.
• Canvas, an interactive UI editor, has been integrated into SwiftUI in favor of the deprecated Interface Builder. Any alterations you make to the presentation’s aesthetic elements will be reflected in the code without you having to lift a finger. This avoids using @IBOutlets and keeps the application from crashing when an association is forgotten to be updated.
• Instead of using AutoLayout, SwiftUI allows you to determine the layout of your views with elements like HStack, VStack, ZStack, Groups, and Lists. These components offer a more natural and consistent approach to designing layouts, as they never result in a non-valid layout and eliminate problems like layout ambiguity and dissatisfaction.
• In addition, SwiftUI has replaced storyboards with code, which makes it simpler to design reusable views and steer clear of disputes that can arise during collaborative development. The overall process of creating iOS app interfaces is simplified and made more user-friendly using SwiftUI.
• With SwiftUI’s latest update, the Share Sheet and the clipboard are now direct access points for your data thanks to the Transferable protocol.

Limitations of SwiftUI

• Being a more recent framework, SwiftUI features less in the way of resources such as tutorials and user forums. You may have a tougher time getting answers to your queries or solutions to your problems because the SwiftUI community while growing quickly, is still smaller.
• You may need to resort to alternative frameworks if you wish to achieve specific effects that are not natively supported by SwiftUI. Although SwiftUI includes a wide variety of inbuilt views and controls, it does not provide nearly many opportunities for customization options.
• For more complicated or tailored layouts, you may need to look outside of SwiftUI and to other frameworks.
• To accommodate previous iOS versions, you may need to go elsewhere for a framework, as SwiftUI’s support is limited in that regard.
• SwiftUI’s lack of compatibility with versions of iOS and Xcode older than 13 is a serious issue. This means that you will have to abandon users on older versions of iOS if you decide to adopt SwiftUI in your app. The fact that many iOS users have yet to upgrade to the most recent version presents a serious challenge to developers that wish to appeal to the widest potential audience.
• Since SwiftUI is still in its infancy, there is a lack of comprehensive resources and answers on sites like Stack Overflow. This can make troubleshooting complex issues you face while using SwiftUI more challenging.
• Finally, the view hierarchy is presently not visible in Xcode Previews when using SwiftUI. This can make it harder to identify and fix underlying causes of UI and behavior problems in your app.

UI testing in Swift

Your app’s UI should function as expected, and UI testing will help you identify any regressions brought on by modifications to UI-related code.

For testing user interfaces, Apple gives us a native framework called XCTest. It leverages information provided by accessible technology to engage with the screen. Writing unit tests is a good analogy for working with these data. Subclassing XCTestCase allows you to add your own methods specifically for testing the UI. To implement this strategy, you’ll need to build code that communicates with elements and then use assertions to ensure that the outcome is as intended.

Three main classes form the foundation of UI test implementation:

• XCUIElement
• XCUIApplication
• XCUIElementQuery

Write your first UI test now that you know the basics!

In this demonstration, you will evaluate TallestTowers, an application that lists and provides details about the world’s tallest buildings. Here’s where you can get the project file.

The highest buildings in the world are ranked and displayed in the TallestTowers project. It is recommended to first switch to the detailed view and then return to the main view in order to verify the navigation. To achieve this, tap on a row in the list to reveal information about that tower, tap the back button to return to the list, and so on until you reach another tower label.

To indicate to Xcode that a method can be tested, you should precede it with the term “test” when writing a test. Let’s make a new function called testNavigation().

func testNavigation() {
// 1
let burjKhalifaPredicate = NSPredicate(format: "label beginswith 'Burj Khalifa'")

// 2
app.tables.buttons.element(matching: burjKhalifaPredicate).tap()

// 3
app.navigationBars.buttons["Tallest Towers"].tap()

// 4
let shanghaiTowerPredicate = NSPredicate(format: "label beginswith 'China'")
app.tables.buttons.element(matching: shanghaiTowerPredicate).tap()
app.navigationBars.buttons["Tallest Towers"].tap()
}

Click the play button next to the test function line to initiate the test. Congratulations! You have now created your first UI test.

Testing Swift UI apps on Real Devices

With App Live, you can test and debug your mobile app in real-time on actual Android and iOS devices through a cloud-based platform. It paves the way for on-the-fly testing without the complexity of setting up and maintaining a private cloud for testing devices.

Using the integrations provided by BrowserStack, upload or install your app files. In a development or staging environment, test apps safely. Use capabilities like network simulation, file and media uploads, geolocation testing, localization testing, and accessibility testing to carry out functional testing. Use development tools to debug and correct problems in your app.

Closing Notes

Writing tests with a deadline looming might be stressful, but it pays off in the end. The integrity of your app’s most important user interface flows can be protected by writing UI tests. Tests help you find regressions before they happen when adding new features or changing code, which speeds up development over time. Planning time for setting up CI/CD for your apps is also recommended. As a result, you can stop worrying about whether or not the app’s UI has been properly tested before releasing it and instead focus on providing a stellar experience for users.