Hundreds of new apps are launched on iOS every day. Every time users download one of these apps, they expect it to perform flawlessly. Even a glitched welcome page or app crash can destroy their trust forever, so iOS app testing is vital to the app development lifecycle.

Snapchat, the widely popular multimedia instant messaging app, experienced firsthand the follies of inadequate testing when a faulty 2018 update led to widespread backlash among its iOS user base and extensive media criticism.

Over a million users signed a petition on Change.org requesting Snapchat revert to the previous version of the app. Although the platform initially defended the update, it eventually rolled back some of the changes and made adjustments in response to user feedback.

The iOS system is complex and has multiple components. It’s known for its high-quality standards and frequently releases new updates with security improvements and API changes.

There are also a large number of devices to contend with, from the newest iPhone models to older devices like iPod Touches, each of which has hardware compatibility. The App Store, moreover, is the sole distribution channel for iOS apps.

That means that your app must always keep pace with its guidelines or risk extra security and even being removed from the storefront. It’s vital, therefore, for your developers to keep pace with these changes and ensure that your apps:

• Have been tested for functionality and user experience on a variety of devices and screen sizes
• Are compatible with new iOS versions while still offering support for older versions
• Are always in strict adherence to App Store guidelines

This way, you can ensure high user satisfaction for the broadest possible range of users, boosting your brand reputation and increasing revenue. Let’s take a closer look at what this entails in this detailed guide.

Types of iOS App Testing

There are seven main types of iOS testing. Let’s talk about each in turn.

1. Functional testing
This is the foundation of iOS app testing. It involves making sure that all features work as intended when interacting with the user interface, APIs, and integrated systems. Areas of focus include:

• Core features like user login and in-app purchases
• Error handling in the form of invalid inputs or network failures
• User flows like creating an account or adding an item to the cart

For instance, you’ll need to test your shopping app to ensure that the user can conveniently purchase selected items, apply discount codes, use their preferred payment methods, and so on.

2. UI/UX testing
It involves testing your app’s visual and interactive features, ensuring that your UI is appealing and easy to navigate and that your UX is engaging throughout the app. Areas of focus include:

• Consistency in the app’s design element and adherence to Apple’s Human Interface guidelines
• Responsiveness to different screen sizes and resolutions without loading problems in the UI
• Intuitive navigation, even for new users

For example, in a social sharing app, you’ll want to test that feed layouts load correctly on different screens and that actions like swiping or one-tap sharing on different apps happen seamlessly.

3. Performance testing
Do you want to see how your app performs under various conditions, including stress testing? Performance testing helps with that and more. Areas of focus include:

• Load testing to see how the app handles large user volumes
• Stress testing by simulating extreme conditions like low battery or limited memory
• Responsiveness when it comes to app loading, screen transitions, and executing tasks

For instance, if your app includes a lot of video media, you’d want to check how those videos play during peak hours, even on slower connections.

4. Compatibility testing
This ensures your app’s compatibility with multiple iOS versions and devices and combinations of the same. Areas of focus include:

• Testing the app on both new and old iOS versions
• Testing that it works across older devices with different hardware configurations
• Checking that the UI displays correctly across different resolutions in both portrait and landscape mode

For example, if your app includes a feature like Face ID, you’ll need to see how it behaves on devices that don’t support Face ID.

5. Security testing
It involves testing your app for vulnerabilities and taking steps to protect your user data. Areas of focus include:

Ensuring that sensitive data (like credit card information) is encrypted in transit as well as in rest

• Testing login mechanisms to ensure that only verified users can access the app
• Addressing common vulnerabilities like insecure data storage or SQL injection
• Ensuring that the app is compliant with relevant regional data standards

For instance, if yours is a banking app, you’ll need to test that every transaction is suitably encrypted and authenticated and that any attempt to bypass security measures is immediately spotted and blocked.

6. Localization testing
This checks how well your app is adapted for different languages and regions if you’re marketing to a global audience. Areas of focus include:

• Ensuring that text is suitably translated, including grammar and context
• Assessing textual and visual content to make sure it’s respectful of different cultures
• Testing with different regional settings like timezone, units of measurement, or currency

For example, if yours is a shopping app, you want to ensure your audiences can see the prices in their home currency, shipping times, or local discounts.

7. Regression testing
This ensures that any new code you’ve introduced into the app hasn’t led to new bugs, especially after an upgrade or a new feature introduction. Areas of focus include:

• Automated testing for predefined performance tests
• Continuous integration to spot issues as early as possible
• Evaluating critical user paths that are most likely to be affected by code changes

For instance, if you’ve newly added social media integration to your app, you want to ensure this hasn’t affected other features like data syncing or making in-app purchases.

Strategies for iOS App Testing to Know for a Strong Foundation

1. Manual testing
As the name suggests, manual testing involves human testers interacting with the app just as an end user would. It helps your testers explore the app beyond the predefined use cases and intuitively catch any potential problem areas.

Reviewing the app’s UI and UX is essential, especially for ease of use and aesthetics. Moreover, manual testing allows testers to quickly adjust focus as circumstances change without the hassle of writing new scripts.

Of course, manual testing is time-consuming, prone to human error, and can be hard to scale as the app grows.

Manual testing is ideal when your goal is exploratory testing to discover new issues or when human judgment is necessary. You can also opt for manual testing for simple apps with limited features.

For example, if you’re launching a basic photo editing app, manual testing can help you determine the appeal of your UI and whether the editing tools are intuitive enough.

2. Automated testing
This involves using scripts to automatically run predefined test cases and get quick results on how well those tests worked. Automation is the way to go for repetitive tasks like regression testing, as the speed and efficiency you get are unmatched.

It’s also much easier to scale and run across multiple devices simultaneously. Automation is much more resource-intensive, so you must set a budget aside accordingly. Some iOS app automated testing frameworks and tools to keep in mind include:

• XCUITest is built on top of XCTest and is perfect for validating UI elements.
• Detox is an end-to-end testing framework that helps you quickly test for complex user interactions.
• XCTest is Apple’s default framework. It’s ideal for unit tests and basic UI tests and integrates well with XCode.
• Appium is a cross-platform tool that lets you write tests for both Android and iOS apps using the same API. Check out this Appium testing tutorial for more information.
• EarlGrey is a native iOS UI automation test framework from Google designed for writing and running functional UI tests. It offers synchronization features that automatically wait for UI elements to be in a steady state, ensuring reliable and consistent test results.

How to Choose the Right Approach to iOS Mobile Application Testing

When it comes to testing your iOS app, both manual and automated testing have important roles to play. You’ll need to strike the right balance depending on various factors, including:

• Project scope and size: Manual testing can be enough when you’re just setting up a simple version of your app. The more features you add, the more automation you’ll need to ensure everything works efficiently.
• Development stage: Many app development companies opt for manual testing during the early stages, focusing more on exploratory testing and determining the needed features. With subsequent versions of the app, automation helps verify continuing functionality even when changes are introduced.
• Budget and resources: Manual testing is a cost-effective option ideal for smaller startups. However, as you grow and continue iterating your app, it makes sense to invest in automation for more consistent results.
• Risk assessment: If you’re on a budget, you can prioritize the aspects of your app that are most vital to get right(such as data security) and invest in automated testing just for those aspects. Later on, you can incorporate automation for other tasks, like regression testing.

How to Set up the iPhone App Testing Environment

1. Xcode and testing tools
Xcode is Apple’s integrated development environment, where you can develop software for all iOS devices.

It consists of a project navigator, a source editor for writing code, a debug area with real-time data about your app’s performance, and a test navigator where you can run and monitor test cases. It also comes with a variety of testing tools, including:

• XCTest, the core testing framework where you write all your app tests
• XCUITest, where you interact with and test your app’s UI elements, such as sending and receiving messages and media on a messaging app
• Instruments, a performance analysis tool that lets you test for things like CPU usage and memory leaks
• iOS simulator, a tool that simulates iOS devices on your Mac, helping you conduct tests across devices without needing physical access to them

2. Configuring simulators and devices
For optimal iOS app testing, you’ll want a combination of simulators and real devices. Both have pros and cons, which you must consider depending on your project’s requirements.

a. iOS simulator
Pros: It’s easy to use and enables faster feedback loops to help you quickly test changes.

Cons: It cannot emulate hardware features like GPS or camera and doesn’t always perfectly mimic devices.

b. Real devices
Pros: This option accurately represents how your app will behave across devices. Plus, you gain access to a full range of hardware features.

Cons: Using real devices for testing can be time-consuming. But more importantly, acquiring and maintaining all possible iOS devices is expensive.

Best practices for using both
Consider opting for device farm services, which give you access to a range of real devices without the need to own them yourself.

At the early stages of development, use simulators for quick feedback and iteration.

Make sure your final tests are on real devices, especially for hardware features and cross-device performance.

3. Test data management
Managing test data is key to ensuring that your tests are repeatable and that they suitably represent real-world scenarios. Types of test data you’ll want to consider include:

• Dynamic data: Data that changes with each test run, like different user accounts
• Static data: Predefined data that stays consistent across tests, like specific product details on a shopping app
• Mock data: Simulated data to mimic the output of services or APIs that the app interacts with, like social media shares

Here are some best practices for managing and creating test data:

• Keep your test data segregated from production data to avoid any disruptions to live systems from your testing activities.
• Use an automated script to generate test data so that each test runs with fresh and realistic data.
• Use version control to manage your test data to ensure greater consistency.

Common Challenges in iOS Mobile App Testing

1. Device fragmentation
The Apple ecosystem consists of a wide range of iOS devices, each with its hardware capabilities and iOS versions, and testing across them with consistent degrees of accuracy can be a challenge.

Older devices, in particular, might have less processing power and lower screen resolutions, which your app needs to accommodate. Having features crash or loading a homepage with misaligned elements can significantly hamper user experience.

For this reason, it’s essential to prioritize testing on all the devices and iOS versions that your customers need the most. A good approach is to invest in a device lab, either cloud-based or physical, to get affordable access to a range of real devices for comprehensive testing.

2. Handling frequent updates
Apple regularly issues major and minor updates to iOS, which can significantly affect APIs and device functionality, affecting how your app behaves.

For example, new iOS versions may introduce new privacy settings that users now expect your app to support, too. You need to be able to incorporate those features without affecting the way your app behaves on an older iOS.

To make this work, we recommend integrating the app with a CI/CD pipeline that automatically runs tests against new iOS beta versions for quicker feedback. You should also implement conditional code paths to ensure backward compatibility with older iOS versions.

3. Network variability
Users may have different network conditions depending on factors like where they are and their network provider. You must test your app’s behavior under conditions such as low connections and intermittent connectivity (like transitioning from WiFi to mobile data and vice versa).

Tools like the Apple Network Link Coordinator can help you simulate different network conditions. Even if the connection fails, your app should have an offline mode to mitigate user frustration.

This is especially important for apps like Google Maps, which need to function offline so that users can navigate their paths in remote areas.

4. Battery and resource constraints
You want to ensure that your app is as battery-efficient as possible and doesn’t use too much memory on any iOS device. This is especially true for features that tend to be resource-heavy, like background processes or GPS tracking.

Running very complex features can also slow down older or lower-end models. To address this, write code that can optimally handle background activities or large datasets and avoid as much as possible unnecessary computations.

The Instruments tool on Xcode can help you with this by profiling your app’s energy and memory usage and pinpointing areas that might be too resource-heavy.

Essential Guidelines for Effective iOS App Testing

1. Test early, test often
In iPhone app testing, it’s vital to integrate testing into each development lifecycle stage rather than just before you release the app. This helps you fix bugs early on, reducing the risk of costly repairs or unnecessary delays.

Plus, continuous testing ensures that any new code doesn’t affect the functionality. Unit testing, incremental integration testing, and frequent builds are all useful ways to ensure that each part of the code works well on its own and in sync with others.

2. Maintain a test log
This is key to helping you organize your iOS app testing process. It includes a detailed record of all tests performed and their results. It’s essential for maintaining traceability, keeping a record of issues and resolutions, and ensuring compliance with regulatory audits.

Write down full details of each test and update in real-time or at the end of every testing session. Use a simple, easy-to-understand format so your entire team can access it and make changes as necessary.

3. Collaborate with development teams
For your iOS app tests to work properly, you want to ensure constant communication between your testers and developers.

This helps both parties better understand what the app needs, leading to faster issue resolution, a better understanding of the tests that need to be conducted, and appropriate reworkings of the code as needed.

A good way to foster better collaboration is to use shared tools and encourage cross-training, where developers learn basic testing skills and vice versa.

4. Keep the focus on user-centric iOS app testing
This involves incorporating user feedback into the testing process to determine whether your app is meeting user expectations.

It’s a helpful way to get real-world insights into how the app works on different devices or contexts, which features and/or bugs need attention first, and whether any pain points in the navigation and ease of use don’t stop during internal testing.

A good way to get user feedback is to release a beta version to a small group of users and refine the app based on their feedback. You can also conduct A/B tests to compare different versions of the same feature.

Final Thoughts

The iOS ecosystem is continuously evolving, and developers and testers need to stay on top of emerging trends and adjust their testing processes accordingly.

Keep evaluating new technologies by signing up for free tool trials, attending industry conferences, or participating in workshops. You should also invest in building a team with cross-platform expertise so that your app performs ideally on ecosystems other than iOS.

Most importantly, we prioritize integrating AI-based testing tools into your environment. AI is at the forefront of the next industrial wave, and the sooner you adopt it, the sooner you’ll see the massive benefits of speed, accuracy, and expanded reach.

Source: This blog was originally published at testgrid.io