Testing iPhone app behavior during interruptions—like calls, low battery, or background refresh—is essential. Including these in your iOS app testing strategy helps ensure your app handles real-world conditions gracefully.

1. Optimizing Your Test Cases for
iOS App Testing

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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

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●​ 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.

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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

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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

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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

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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.

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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.
●​ 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.

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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.

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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

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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.

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●​ 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.

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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.

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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.

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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.

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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.

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The Evolving Landscape of iOS App
Testing: What Does the Future Hold?
As more emerging technologies enter the market, iOS app testing is
continuously evolving, so your testers and developers must keep adjusting
their strategy to stay relevant. Some trends to keep in mind include:
●​ Self-healing tests: AI-powered test frameworks can create self-healing
tests that automatically adjust test scripts to app UI changes.
●​ Predictive analytics: Artificial Intelligence (AI) and Machine Learning
(ML) are increasingly used to study historical test data and predict
potential areas of failure, making for more efficient test prioritization.
●​ Automated test generation: ML algorithms can study user behavior to
automatically generate tests for edge cases that manual design might
overlook.
●​ Cloud-based testing platforms: The cloud enables a much more
scalable and cost-effective testing environment. You can access a wide
range of devices and configurations without needing your own physical
hardware. This also enables better real-time collaboration among teams
in different locations.
So, how do you adapt to new technologies for effective iOS mobile app
testing?
●​ Invest in specialized tools that can simulate different real-world
scenarios and environments for different types of testing.

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●​ Take into account the unique challenges of new types of technology,
such as testing how an AR/VR app interacts with iOS devices, hardware
sensors, and the environment (such as virtual furniture in a user’s
room).
●​ Ensure that the UI on wearables like fitness watches (which have much
smaller screens than iPhones or iPads) is designed to be accessible to
the user and fully functional with the wearable hardware capacity.
●​ When testing devices in an IoT ecosystem, check that the app can
seamlessly communicate across those devices, regardless of device
type or network conditions.
●​ Make sure that the app always handles user data securely, regardless of
any integrations or device connections, even if the user is accessing the
device remotely.
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.
Source: Interested readers may also refer to TestGrid for more details.