Testing Mobile Apps: Step-By-Step Guide

Technology is growing every day and so is the use of mobile phones in our lives. For as little as ordering groceries for our homes to handling our finances through banking and other financial apps, mobile applications are an integral part of our daily activities. With such rapid growth and absorption of mobile apps in our day-to-day activities, ensuring their quality and functionality has become paramount. Mobile testing is a crucial process to validate the performance, usability, and compatibility of mobile applications across different devices, operating systems, and network conditions. In this article, we will navigate through a comprehensive overview of mobile app testing, covering its importance, types, challenges, and best practices.

What Is the Importance of Mobile App Testing?

Mobile applications can be tricky as compared to their desktop counterparts. Similarly testing mobile applications can come with its own set of challenges, which is why testing the applications thoroughly becomes all the more important. Some of the reasons that explain the importance of mobile app testing are:

1. The mobile device market is huge, with numerous devices, screen sizes, resolutions, and hardware specifications. Testing apps across this diverse range of devices is crucial to ensure the reliability of the mobile apps.
2. Mobile device operating systems(Android, iOS, etc.) have frequent updates, each with its own set of features. Testing ensures the compatibility of the applications across these different versions.
3. Your mobile device relies on network connectivity, which depends on the location, carrier, and signal strength. Testing the applications by simulating different network conditions, including low bandwidth, high latency, and intermittent connectivity can help greatly.
4.  Mobile devices provide on-the-go usage focusing on intuitive and user-friendly interfaces. Testing helps to prioritize usability and ensures a seamless user experience across various devices and scenarios.

All the above factors emphasize the need for testing mobile applications thoroughly across different devices and operating system combinations.

Mobile App Testing: What To Test?

Mobile applications are loaded with features, and testing them thoroughly helps to ensure a seamless and high-quality user experience. Apart from the functionality of the application, some of the key features that should be tested are:

• User Interface and User Experience(UI/UX): Mobile app testing primarily focuses on the evaluation of the app’s interface, its elements, layouts, navigation, and overall user experience. Testers should assess the application’s UI across different screen sizes, resolutions, and orientations to ensure consistency and usability. The UI components should render properly, and be responsive.
• Functionality: Mobile app testing involves thorough validation of the app’s core functionalities, features, and user journeys. The app’s business logic, data input/output operations, calculations, and other functional aspects should be validated to be working as expected across different devices, operating systems, and scenarios.
• Input methods and gestures: Mobile apps heavily rely on touch gestures like swipe, pinch, tap, etc. Additionally, various input methods like on-screen keyboard, and voice input are used to input the data. Testing these capabilities ensures a smooth user experience.
• Multitasking and interruptions: Mobile apps often run in the background, or there may be interruptions like incoming calls, notifications, etc. Testing evaluates how the application handles such scenarios without any data loss, corruption, or deviated behavior.
• Network and connectivity: Mobile apps work through network connectivity, be it Wi-Fi, or cellular data. Testing can help uncover issues under different network conditions.
• Performance and resource utilization: Since mobile devices are built on limited resources like processing power, battery life, and memory, testers can identify performance issues in the app corresponding to responsiveness, loading times, and resource utilization under different conditions.
• Security and data protection: Data is of utmost importance to the users. Mobile apps handle sensitive user data, making the need to assess the security of the application a critical aspect. Testing can help identify and mitigate potential vulnerabilities, like, data leaks, insecure communication channels, unauthorized access attempts, etc. It can also help in complying with relevant data protection regulations like GDPR, CCPA, etc.
• Localization and internationalization: A lot of apps target a global audience, localization, and internationalization testing help in ensuring that the app’s content, formatting, and functionality are adapted for different regions, languages, locales, and cultural conventions.
• Compatibility and interoperability: As a user, you may use the mobile application on any device, and any operating system. To ensure that the application works consistently on different platforms and hardware, compatibility testing is the way to go. Interoperability testing on the other hand verifies that the app integrates and communicates properly with other installed apps, or some external system.
• Installation and updates: To start using an app in the first place, it needs to be installed properly. Testing the app’s installation process, update mechanisms, and compatibility with different installation sources is crucial for a good user experience and prevents any conflicts.

Types of Mobile Apps

Based on the development approach, mobile apps can be categorized into the following types:

• Native apps: Native apps are developed for a particular operating system, for example, iOS or Android. These apps use the platform’s native programming language and development tools. For Android native apps are developed using Java or Kotlin while for iOS they are built using Swift or Objective-C. Native apps offer the best performance, seamless integration with device hardware and APIs, and user experience that aligns with the platform design guidelines.
• Hybrid apps: Hybrid apps are sort of part native apps with web browsers embedded. These are built using web technologies like HTML, CSS, or Javascript and wrapped in a native container that provides access to device features and APIs. Cross-platform frameworks like React Native, Flutter, or Ionic are used to develop hybrid apps. These apps allow for code reuse across multiple platforms, hence reducing the development cost and time to market. However, as compared to native apps they may compromise on performance and native look and feel.
• Web apps: Web Apps are also known as progressive web apps(PWAs). These are mobile-optimized websites that run in a web browser and can also be added to the device’s home screen for an app-like experience. Standard web technologies like HTML, CSS, and JavaScript are used to develop them and unlike the native and hybrid apps, do not require installation from the app store. Web apps offer cross-platform compatibility and easier distribution but may have limited access to the device hardware and APIs as compared to native or hybrid apps.

Mobile App Testing: Types

Mobile app testing can be broadly categorized into functional and non-functional testing. These types are further classified into different types of testing as discussed below.

Functional Testing

As the name suggests, Functional testing aims to test the functionality of the application. It can be diversified into the following types:

1. Installation and setup testing: This verifies the app’s installation and setup process and its compatibility with different devices and operating systems.
2. User Interface(UI) testing: It validates the app’s UI elements, layout, navigation, and usability across different screen sizes and orientations. Additionally, you may want to see how the different gestures work for the app. 
3. Functionality testing: It ensures that the app’s features and functionalities work as expected, including user workflows, and business logic.
4. Integration testing: It is used to test the app’s integration with external or third-party systems.
5. Geolocation testing: It validates the app’s content, formatting, and functionality based on the location where the app is being accessed.

Other aspects like data integrity, interruptions, and input testing can be carried out under functional testing.

Non-Functional Testing

Unlike functional testing, non-functional testing aims to asses the non-functional parameters of the application.

1. Performance testing: Assesses the app’s responsiveness, loading times, and resource utilization under various conditions and user loads.
2. Security testing: Potential vulnerabilities are identified and mitigated as a part of security testing to prevent unauthorized access and data breaches.
3. Usability testing: It helps in evaluating the app’s user interface and overall user experience through real user interaction.
4. Compatibility testing: The app’s compatibility with varied devices, operating system, and their versions is assessed through compatibility testing.
5. Stress and load testing: It helps to test the app’s ability to handle high volumes of concurrent users, data, or transactions without any failure or performance degradation.
6. Accessibility testing: It ensures that the app is accessible to users with special requirements, or disabilities, adhering to relevant accessibility standards.
7. Battery and power consumption testing: This is used to assess the app’s impact on the battery and power consumption of the device. This is particularly important for resource-intensive or location-based apps.

How To Select the Right Device for Testing

Choosing the right device for mobile app testing is as important as testing in the right environment. It is crucial to ensure that the test coverage is comprehensive and covers different platforms, operating systems, and hardware configurations. Some important points that help in making informed decisions while selecting a device for testing are-

Target Audience and Market

It is important to consider the devices used by your target audience that would be interacting with the app, along with the regions it would be released. Analyze market data and user demographics to identify the most commonly used devices and platforms.

Operating System Versions

The latest stable versions of the operating systems as well as previous versions that are still widely used by your target audience need to be tested. It is essential to ensure compatibility across different OS versions.

Device Fragmentation

Always include a diverse range of devices with different screen sizes, resolutions, hardware specifications, and sensor configurations to account for fragmentation in the mobile device ecosystem.

Form Factors

Depending on your app’s functionality, consider testing on different form factors like smartphones, tablets, or wearables(like smartwatches). The app should adapt to the different screen sizes and input methods without any issues.

Network Carriers and Connectivity

Devices with different network carriers and simulations of different network conditions should be considered while testing to ensure reliable performance and identify any potential connectivity-related issues.

Real Devices and Emulators/Simulators

You should incorporate both real physical devices and emulators/simulators in your test strategy to widen your test coverage.

Mobile Testing Strategies: Manual and Automation

For comprehensive coverage and an efficient test process, both manual and automated testing help in creating a robust mobile testing strategy. 

Manual Testing

• Exploratory testing: Manual exploratory testing allows testers to discover and investigate issues that may be missed by predefined test cases. This helps to identify unexpected behaviors and edge cases.
• Usability testing: Real users can give deep insights into the user interface, navigation, and overall user experience. Usability testing provides information on how the user perceives the app, highlighting the areas of improvement.
• Ad-hoc testing: Unscripted testing based on the tester’s experience can be useful in identifying edge cases and unexpected behaviors that might be missed by scripted test cases.
• Session-based testing – Time-boxed testing sessions with a focus on specific areas help to manage testing efforts effectively and ensure coverage of critical scenarios.

Automation Testing

• Unit testing: Automating individual units of the app’s codebase can help catch defects early in the development cycle. Additionally, it also helps in ensuring that individual units of code are working as expected.
• UI automation: Automating the app’s user interface, simulating user interactions, and validating the UI elements and workflows can help uncover issues across a wide range of devices with a single framework.
• API testing: Automating the backend APIs of the app helps in ensuring correct functionality, data integrity, and performance. Apps relying on external data sources or third-party services can benefit a lot through API automation.
• Performance and load testing: Automating the performance benchmarks to assess the responsiveness and behavior of the app under various load conditions helps in identifying performance bottlenecks. The insights gathered from it can be used to optimize the app for optimal resource utilization.
• Security testing: Security vulnerabilities like data leaks, insecure communication channels, or unauthorized access issues can be easily identified by automating the security tests.
• Regression testing: Automation of the regression suite is highly beneficial to ensure that new changes have not introduced bugs in existing features. It helps in maintaining the quality and stability of the app.

For the mobile testing strategy to be successful, it is important to combine both manual and automation testing approaches. You should consider leveraging the strengths of each to achieve comprehensive and efficient coverage with timely feedback.

Mobile App Testing: Challenges

Mobile testing comes with its own sets of challenges that should be addressed to achieve quality and reliability.

1. There are a lot of mobile devices and operating system versions available in the market today. These devices and operating systems are growing every day with new updates. It can be difficult to maintain a pool of devices for testing. Hence, keeping up with the testing infrastructure can be resource-intensive
2. Mobile apps often have frequent releases and updates. This can put pressure on the testing team to deliver thoroughly tested apps within strict timeframes.
3. Certain real-world network conditions can be difficult to replicate, which can impact the app’s performance.
4. As compared to automating the traditional web app, mobile app automation can be complex due to gesture-based interactions, or sensors. Maintaining test scripts in such cases can be time-consuming and require specialized skills.
5. Evaluating the user experience of an app can be subjective. Involving real users is crucial but can be resource-intensive and time-consuming.

Mobile App Testing: Best Practices

Industry best practices can help overcome the challenges of mobile testing.

• Define a clear and comprehensive testing strategy that goes by the app’s requirements, target audience, and supported platforms. Testing efforts should be prioritized based on risk, impact, and critical functionality.
• Continuous integration and Continuous Testing(CI/CT), can help catch the issues due to code changes early in the development lifecycle.
• Cloud-based testing services that offer a diverse range of real devices, reduce the overhead of maintaining an extensive in-house device lab.
• Use tools that help simulate real-world network conditions, device sensors, and interruptions to ensure a realistic testing environment.
• Adopt test automation frameworks like Appium, Espresso, and XCUITest to create and maintain test suites efficiently.
• Collaborate with the development and user experience teams to ensure a shared understanding of requirements.
• Ensure regular monitoring and analysis of test results to identify patterns and deviations. This will help in making informed decisions about prioritizing test efforts and addressing issues.
• Mobile technology is constantly evolving. It is essential to stay informed about the latest trends and best practices to improve the mobile testing approach.
• Crowdsourced test platforms can provide access to a diverse pool of real users, which can help in gathering real-world user feedback.

Mobile App Testing: Tools and Technologies

Mobile app testing involves a wide variety of tools and technologies. Some of the popularly used ones are:

1. Appium: Appium is an open-source test automation framework that supports both Android and iOS platforms. Testers can write and execute tests across multiple devices and platforms using programming languages like Java, Python, Ruby, and more. It provides cross-platform compatibility, ease of use, and extensive community support.
2. Espresso: Espresso is the official test automation framework of Google for Android apps. It comes with a set of APIs and utilities designed specifically for UI testing on Android devices. It comes with features like test recorders, synchronization capabilities, and integration with Android Studio.
3. Katalon Studio: It is a comprehensive test automation solution that supports web, mobile, and API testing. It comes with a user-friendly interface, allowing integration with testing frameworks like Appium and Selenium.
4. XCUITest- XCUITest is Apple’s testing framework for iOS apps. It is tightly integrated with XCode(Apple’s IDE for iOS development) and supports testing on real devices as well as simulators.

5. TestGrid.io: TestGrid is a comprehensive testing platform that empowers you to handle both manual and automated testing efficiently. Not only is it equipped with a Real Device Cloud offering a wide variety of devices on the run, but it also comes with a codeless automation testing solution. It allows testers to create and manage tests by simply recording their actions and converting them to a script. Additionally, you may use custom scripts or integrate your local Appium or Selenium code as per the needs of your project. 

Apart from these popular mobile testing tools, you can leverage Apache Jmeter or Gatling for performance testing and security testing tools like OWASP ZAP.

Key Takeaways

• Mobile app testing is crucial for the success of your applications in the ever-competitive and growing landscape. Factors like device fragmentation, operating system versions, network conditions, battery life, user experience considerations, etc highlight the importance of mobile app testing.
• Mobile testing can be functional or non-functional where each cover, UI functionality, gestures, data input, interruptions, data integrity, and performance, security, compatibility, localization, and network respectively.
• Mobile apps can be classified into native apps- built for specific platforms, hybrid apps- web technologies wrapped in native containers, and web apps- mobile-optimized websites.
• When it comes to selecting the right device for testing, consider factors like target audience, form factors, network carriers, real devices v/s emulators/simulators, budget constraints, etc.
• An efficient mobile testing strategy is a combination of manual as well as automated testing.
• Challenges of device fragmentation, rapid release cycles, limited testing resources, automation complexities, and user experience testing can create hindrances in the mobile testing approach. To overcome them best practices which include developing a comprehensive testing strategy, simulating real-world conditions, embracing test automation, using cloud-based testing services, and staying up-to-date with the industry trends can help.