20+ Mobile App Testing Types, Approaches, and Strategies

SDLC for a mobile program can become messy, tedious, and quite challenging due to its intricacy and variability. An integral part of the process that arguably has one of the largest impacts on the outcome is QA. To streamline the testing procedures and make the development less strained, let’s dive into the commonalities and specialties of mobile app testing.

Particularities of Mobile Testing

When it comes to mobile QA, there are some subtle aspects that distinguish it from desktop and web app testing. In particular, while working with a mobile application, consider the following:

1. Installation / de-installation / update process.
2. Location & VPN.
3. Data synchronization.
4. Interruptions of the application by cells, messages, etc.
5. An ability to run the app in the background.
6. Payment gateway.
7. Communication (chat, audio, video).
8. Touchscreen (tap, swipe, pull, shake, pinch).
9. Voice commands.

Moreover, there would be some differences regarding the work scope depending on the type of app and platform under testing.

Mobile App Types: Native and Hybrid

Any mobile app testing company often works with multiple types of mobile applications – native, hybrid, and PWA. PWA apps can function as regular mobile applications and separate websites at the same time. Think Twitter’s app and desktop versions – both are essentially one program. We’ll focus on native and hybrid as the third one borders with another subject.

• Native mobile apps are developed for a specific platform – Android or iOS. So if a service is present in both stores, these are two separate applications.
• Hybrid mobile apps are universal, so one app can be installed on both platforms. It is possible due to combining native and web elements in the development.

While this duo have their specifics, the testing approach will be the same for either app type.

• They use different underlying technologies, but the end functionality would be the same regardless of the chosen solution. So, the functional checklists or test cases will focus on traditional evaluations.
• Performance issues are more common in hybrid apps. Though they aren’t necessarily slow, it makes sense to pay more attention to performance when testing a hybrid app. Packing web technologies inside a native shell can make an app heavier and less responsive compared to a native one.
• Similarly, UI testing will take more time when working with hybrid applications. The variety of Android devices, and therefore, screen sizes and resolutions, is truly impressive, so to speak. So, for hybrid apps, the UI should be fitted not only to each Android gadget, but the iOS versions as well.
• Take the colossal list of screen sizes and resolutions and add all the OS versions and variations. You’ll get quite a lot of software/hardware combinations for testing. It means that testing of hybrid apps tends to require more real devices for compatibility testing than native app testing.

Testing Hybrid Applications: Particularities and Challenges

Mobile App OS: Android App Testing and iOS App Testing

In general, Android and iOS testing wouldn’t be significantly different. It’s similar to the case above – the main dissimilarity would be the time necessary for testing. Naturally, testing an iPhone app will take less time.

Android is represented by an ampler variety of devices and OS versions. Thus, there is a bigger scope of work for Android device testing when it comes to cross-platform checks. To be more specific:

• Since Android devices come with more screen sizes and resolutions, there is more room for layout issues and interface bugs. Thus, the scope of tasks for UI testing is also bigger compared to iOS.
• Android offers lots of software and hardware configurations, so again, performance and compatibility testing would require more time.

Mobile App Needs: Real-Device Testing

Testing on real devices allows a QA team to ensure that an application works smoothly on a variety of smartphones. For example, only when using a real device, one can properly check:

• colors on screens with different resolutions;
• touchscreen with all the swipes, scrolls, and taps;
• location tracking, camera, audio, and other device-specific features;
• different software and hardware configurations;
• performance during interruptions, background operations, and CPU consumption.

Further, properly evaluating basic usability aspects (e.g., readability and convenience of buttons) is possible exclusively with real-device testing. The same goes for battery life: you can see whether an app drains the battery only by using an app in real time.

Types of Testing for Mobile Applications

While mobile app testing has its peculiarities, it is no stranger to traditional check-ups. The QA legacy demonstrates that there are no easy solutions for a quality result. And that is why mobile applications need to undergo these core testing types on their way to a great product.

Functional Testing

This mobile testing type ensures that every function of an application is working as intended and acting by predetermined requirements.

Frequently, functional testing focuses on user flows within the app and the features that comprise them. This method applies black-box testing techniques to evaluate a system. As black-box translates to the absence of knowledge of the internal logic, it presents a fuller picture of app’s functionality from users’ POV.

What functional testing covers is directly dependent on the intended industry and audience. Some features, however, will be common regardless of the app attributes. For example, it is crucial to assess:

• installation/uninstallation of an app on different devices;
• registration and login, password change and restoration;
• editing and updating account information;
• checking the looks and functions graphical elements – fields, buttons, icons, menus.

These elements present most usefulness to end-users. Hence, extra effort should be directed toward reviewing core consumer operations.

What is Functional Testing and How to Run It?

User Interface (UI)

UI testing is the examination of the visual part of a mobile app an end-user comes in contact with. It means testing the graphical elements to verify that they are functioning according to the requirements.

UI testing covers the gamut of visual indicators and graphic-based icons – toolbars, fonts, menus, text boxes, buttons, checkboxes, colors, and more. Actions a user is able to perform, i.e., UI gestures like touching, tapping, dragging, and swiping, fall under this testing as well.

The essential test cases cover the design and functionality of the following elements:

• Navigation
• Progress bars
• Shortcuts
• Input fields
• Banners
• Buttons
• Checkboxes
• and more

Additionally, micro-interactions are becoming more prevalent. These small details allow users to better understand an app. For instance, that small red circle on the Gmail application’s icon signals that there is a new message. A scroll bar at the screen’s side permits to better navigate the page. Such tiny features make UI stand out and should be properly tested to offer optimal experience.

Usability Testing (UX)

Before discussing mobile usability testing, you need to make sure you understand the difference between UI and UX. In short, UI encompasses visual aspects of software design, while UX refers to the emotional aspects of the interaction with the software.

Usability answers the questions:

• Can the users accomplish their goals easily?
• Do they understand how to work with this app without any problem?
• Is it convenient?

UX testing allows measuring an app’s user-friendliness and revealing ways to support the brand’s marketing objectives.

Checking the usability of an application includes:

1. Evaluating the compliance of the application design with its functionality specified by the customer.
2. Analyzing the used graphic elements and color design in terms of perception.
3. Assessing the usability of application features.

A full-scale UX inspection is a task for a designer or a marketing team. Still, a QA team can run basic UX checks.

The Difference Between UI and UX, and Ways to Test Each

Compatibility Testing

To put it simply, it ensures the consistent functioning of an app across devices and software ecosystems. This includes checking how an application behaves on devices with different hardware configurations, network conditions, displays, built-in features, apps running in the background, etc.

Using real devices here is especially important. Though emulators and simulators can be involved at the initial stages, they are not as effective as physical smartphones that can mimic all the aspects of user’s interactions with a program.

During compatibility testing, you need to pay attention to:

• functioning on different operating systems and their versions;
• performance under different network conditions and their parameters;
• look and functionality on various browsers and versions;
• the user interface on different screen sizes and resolutions.

The key ideas of compatibility testing for mobile devices are pretty much the same as for testing in general: identifying risk zones before the app launch, revealing critical bugs and verifying that they don’t go to production, and making the maintenance and scaling smoother.

How to Choose the Right Devices for Compatibility Testing?

Accessibility Testing

Companies should strive to ensure the same (and pleasant) experience for everyone, including users with cognitive and physical disabilities. To run mobile accessibility testing is to verify that an app has been adjusted for various needs. These could be a great starting point:

• keyboard shortcuts;
• zooming functions;
• fonts, contrast ratio, and other color settings;
• sassistive technologies (voice search & screen readers);
• tooltips & user guidelines.

These might seem like little things, but they can mean a lot for people who need them and businesses that want to show support and amplify their reach.

Performance Testing

Performance problems with mobile apps can lead to customer and revenue losses, brand image harm, and business goal interruptions. Mobile app performance testing is what helps prevent it all.

There are several types of mobile performance testing:

• Load testing – focuses on performance under normal conditions.
• Stress testing – operability and performance of the application under extreme loads.
• Stability testing – examines an application’s long-term performance.
• Volume testing – performance with increased volumes of processed data.

In general, performance testing helps outline an app’s stability, resource consumption, ability to withstand high loads, and make sure there are no smartphone freezes.

Common Performance and Load Issues, or Why Performance Testing Matters

Localization Testing

Localization testing allows ensuring that an application has been adjusted to a target market in terms of language, representation, and cultural characteristics of a particular region.

For instance, Arabic, Hebrew, and Pashto cultures have right-to-left writing. Near East, China, and Africa use fully or partially logographic writing. Developers should consider this when coding input fields, and QA engineers should be quick to notice any disparities. Localization also covers compliance with local legal requirements, in-app hyperlinks, content and UI, and testing on the devices widely used in a specific area.

The goal of localization testing is to guarantee that an application looks and feels most familiar to the users in a specific region.

What is Localization Testing?

Internationalization Testing

Internalization testing, on the other hand, provides for an app’s adaptability to multiple regions. So, instead of highlighting the local features, it aims to make the content and functionality universal – suitable for different audiences with or without particular adjustments.

This testing type is useful for increased visibility and personalized app rendering. For example, Google’s search page logo changes depending on an important date, be it an international holiday or a region-specific event.

Security Testing

From credit card encryption on a shopping app to internal system defenses, security testing governs the crucial aspect of data protection. So much so that it has become a separate branch of the QA process.

Mobile application security testing checks include:

• mobile app pen testing;
• vulnerability scanning;
• risk assessment;
• technical audit;
• red-blue teaming, and more.

All of the mentioned inspections allow for uncovering existing and potential vulnerabilities, threats, risks in a mobile application, and loopholes in the processes.

Change-Related Testing

Change is inevitable. Even when an app’s progress is going according to plan. Once developers fix reported issues, QA engineers need to run several checks again to verify the alterations and make sure the rest of the functionality is still working.

There are several types of change-related testing:

• Retesting means repeating the tests for the functionality where a bug has been fixed and confirming it doesn’t appear anymore.
• Smoke testing allows determining if a build is stable and can be subjected to further testing (e.g., installation and logging in are successful, thus further testing is viable).
• Regression testing covers the unchanged parts of a mobile app to learn if code alterations haven’t affected the existing functionality.
• Sanity testing is a random examination of relatively stable builds with minor changes to check the overall operations logic.

While it is always better to cover all fronts, these types of mobile app testing can have greater value for specific projects and needs. For instance, smoke testing is good for MVPs, regression – for final releases, and sanity – for tight deadlines.

Regression, Smoke, and Sanity Testing – What’s the Difference?

API Testing

An API (application programming interface) is a set of protocols and tools that enable communication between software systems or functions. It connects mobile apps to streamline internal operations or links external systems to extend the application’s capabilities.

Here’s an example. A user is searching for a hotel room in Vilnius through a booking app. They fill in the check-in and check-out dates, the number of guests, and other details. Then, they click the search button. For a result to pop up, the application ‘communicates’ with other programs that have relevant data and filters desired properties.

Essentially, pressing the ‘Search’ encourages the app to interact with multiple servers through an API to collect needed info and display suitable options. Thus, API acts as a bridge connecting functionally distant programs.

So, during API testing, the interface itself is checked, i.e., the ability to link and work with other software. For a proper API, the following should be evaluated:

• documentation;
• functionality;
• performance;
• security;
• basic usability.

API should be able to handle expected loads (e.g., many users requesting to connect to the same database). That is why performance testing for API should be among top priorities. While QA specialists can wait until the interface is completed to run tests, for a speedier procedure, they can work with the API level separately.

An Introduction to API Testing

End-to-End (E2E) Testing

During end-to-end testing, a QA engineer checks a user journey from start to finish. It gives a clear perspective of the path a user takes to accomplish a particular goal. Hence, what E2E testing does is:

• simulating a user scenario;
• validating the system under test (components of the app, UI flow, and API);
• making sure the system behaves as expected.

To better grasp E2E, let’s quickly review a shopping app. A roadmap for E2E testing would start with opening an app and finish with a success message about the purchase. In this way, end-to-end testing centers on the consumer and how they interact with the app.

What Is End-to-End Testing?

Acceptance Testing

Mobile acceptance testing is the final verification of the business functionality. It is the last step taken to guarantee the expected functioning of a system. Within this testing type are:

• User acceptance testing – assessing the final version of an app (may be performed by a business representative or an actual user).
• Business acceptance testing – verifying compliance with set business goals.
• Contract acceptance testing – checking conformity to predefined criteria within a contract outlining an app’s deliverables.
• Regulations acceptance testing – evaluating abidance with specifications from regulatory agencies.
• Operational acceptance testing – confirming an app’s operational readiness.
• Alpha and beta testing – testing an app in development by an expert and testing an app pre-release by users.

Combined, these testing types ensure positive UX, satisfied stakeholders, and regulatory compliance.

What Is User Acceptance Testing and How to Run It?

Mobile App Testing Approaches

Whether testing is run by QA specialists or developers, the best QA strategy is to test early. Still, there are a few approaches to testing that, while have the same goal, differ in timeframes.

Proactive Approach

As the name implies, a test design process starts early and aims to prevent issues even before the code is ready. Instead of checking the final or close to the final version of a mobile application, a QA team starts with a requirements review. Thus, instead of finding bugs, they help prevent them and shape software quality from the very beginning.

Reactive Approach

This approach, on the contrary, implies working with an end-product, when its design and functionality are supposedly ready for use. Using the reactive approach, a testing team waits to run tests at the late stage of an SDLC. In a way, they “react” to the quality of the delivered product.

Mobile App Testing Techniques

As an ISTQB defines it, a testing techniques is a procedure used to define test conditions, design test cases, and specify test data. Let’s take a look at two techniques for now: static and dynamic testing

Static Testing

Static testing means examining an app without executing the code. Instead of function-centricity, experts review the code in order to find any errors within the foundational layer of an application. The goal is to establish requirements and documentation that are targeted at preventing any issues.

Dynamic testing

Dynamic testing means evaluating an app during its execution. This is the classical approach to testing. Guided by designed testing data, QA engineers check app’s functions and layers – from unit to UI. This method is highly compatible with mobile automation testing.

To Sum Up

Some may think that working on an app for smaller devices renders the software simpler. But there is no aspect of mobile app testing that is simple. In order to create a top solution for users’ desires, the team needs to consider both customary and unique features of mobile applications. Adhering to testing traditions and smartly leveraging particular mobile app needs is what makes any project a success story.