Mobile apps have become a critical part of our daily lives. As per Statista, the number of mobile users across the globe is expected to reach a whopping 7.5 billion by 2025. On average, we spend over 4 hours a day on our mobile devices. Moreover, over 90% of this time is typically spent in mobile apps rather than mobile web browsing.
These statistics clearly highlight our deep engagement with mobile apps. However, while over 2 million apps were launched just in 2021, a staggering over 60% of users abandon apps with too many bugs and a subpar user experience.
This is where comprehensive mobile app testing enters the picture. Thorough testing across multiple dimensions can help companies detect critical issues early, enhance user satisfaction, reduce costs, minimize risks, and boost the chances of app success.
In this detailed guide, we will explore the what, why and how of mobile app testing. We will also cover the 6 most important types of mobile app testing and provide actionable tips for testers and development teams. Let‘s get started!
What is Mobile App Testing?
Mobile app testing refers to the practice of testing mobile apps across various parameters to ensure they function as desired and meet business and user expectations. It is a key subset of software testing that focuses on validating mobile applications.
Mobile app testing aims to:
- Validate functionality – Do all features and modules work as intended?
- Evaluate usability – How easy and intuitive is the app for users?
- Assess performance – Does the app respond quickly and work well?
- Check compatibility – Does the app work on diverse devices and platforms?
- Identify security issues – Are there vulnerabilities open to exploitation?
- Compare to requirements – Does the app meet business needs?
Proper mobile testing requires methodically testing the application on various devices and platforms under different conditions to uncover flaws and gaps.
Why is mobile testing important?
- It results in higher quality apps with better stability, security and user experience.
- It reduces development costs by detecting bugs early that are cheaper to fix.
- It provides insights to enhance UI/UX design and features.
- It minimizes risk of issues impacting reputation and finances.
- It increases user retention and engagement.
When does testing occur?
Testing activities start early during mobile app development and continue through launch. Key testing stages include:
- Unit testing – for individual modules and components
- Integration testing – to validate modules work together properly
- User acceptance testing (UAT) – final validation against original requirements
Incorporating mobile testing across the development lifecycle is crucial for delivering high-performing, glitch-free apps that users love.
6 Critical Types of Mobile App Testing
There are 6 key testing types that mobile QA teams need to perform to deliver maximum value:
1. Functional Testing
This tests core app functionality. The focus is on validating that key features, workflows, integrations and modules perform as intended.
What to test:
- Input forms, buttons, navigation, menus
- Workflows and user journeys
- Integrations with OS, device features and external services
- Calculations, payments, transactions
- Error and exception handling
As an example, functional testing would verify:
- Tapping on a button launches the right feature
- Entering text in a form field works properly
- Errors are handled gracefully allowing users to recover
Best practices:
- Leverage test automation to execute frequent regression testing
- Prioritize testing critical app functionality and workflows
- Perform exploratory testing to uncover edge cases
In my experience, test automation is invaluable for rapidly validating new versions and builds during rapid development cycles. I would recommend using open source tools like Appium and Selendroid for test automation.
2. Usability Testing
This testing focuses on evaluating ease of use and the user interface (UI). The goal is to uncover any obstacles to simple, intuitive interactions.
What to test:
- Layout, visual hierarchy and flow
- Content presentation and messaging
- Simplicity and ease of completing tasks
- Error states and recoverability
As an example, usability testing would assess:
- How obvious call to actions (CTAs) are on each screen
- If menus and options are easy to find
- How difficult it is for users to recover from errors
Best practices:
- Conduct usability testing early and often, even on wireframes or prototypes
- Leverage tools like UserTesting.com to gather feedback at scale
- Directly observe real users interacting with the app to uncover pain points
In the past, I have gathered tremendous insights by sitting with 5 end users and having them complete tasks on early app prototypes. Their feedback led to dramatic UX improvements before coding even began!
3. Compatibility Testing
This involves testing the mobile app on various mobile devices, browsers, operating systems and networks to ensure seamless experience under diverse conditions.
What to test:
- Different device models, OS versions, screen sizes
- Various mobile browsers (Chrome, Safari, Firefox etc)
- Cellular networks (3G/4G/5G) and WiFi
- Operating under load, switching between networks/apps
For example, compatibility testing would validate:
- App layout adapts correctly to different phone sizes
- Smooth functioning when switching between WiFi and cellular
- Performance isn‘t impacted by OS updates
Best practices:
- Test on both Android and iOS to cover majority of market
- Utilize emulators and simulators for fast testing at scale
- Perform on real end-user devices under varying networks
- Test early with demos to uncover incompatibilities
In the past, I uncovered compatbility bugs that only appeared when testing on older OS versions still used by millions of users. Extensive compatibility testing is crucial.
4. Performance Testing
This testing focuses on evaluating the app‘s performance under expected user load and use cases. The goal is to find and fix bottlenecks.
What to test:
- Functionality and response times under heavy load
- Impact of background activity, network changes etc
- Resource usage – memory, network, battery
For instance, performance tests would assess:
- Degradation in response times as load increases
- Battery and memory impact over prolonged use
- Network usage when switching between WiFi and cellular
Best practices:
- Identify critical use cases and bottlenecks upfront
- Test with production-level data early to find issues
- Use tools like JMeter to simulate real-world load
In the past, I‘ve used JMeter to simulate thousands of concurrent users which revealed database bottlenecks not visible during basic testing. Addressing them led to 10x improvements in response times.
5. Security Testing
This critical testing checks the app for potential security vulnerabilities that could lead to exploits, data breaches and attacks.
What to test:
- Authentication mechanisms and access controls
- Encryption of cached, stored and transmitted data
- Prevention of common attacks – injection, cross-site scripting etc
- Input validation and sanitization
For example, security tests would verify:
- Inputs are sanitized to prevent code injection
- User sessions are securely managed
- Unauthorized access is prevented
Best practices:
- Perform penetration testing to find vulnerabilities
- Analyze code for common flaws like SQLi, XSS etc
- Stay up-to-date on evolving attack techniques
- Follow OWASP Mobile Top 10 guidelines
In the past, penetration tests have revealed critical issues even in mature apps built by large engineering teams. Never overlook security testing.
6. Interface Testing
This testing focuses on UI elements and validating they function and display correctly across different environments.
What to test:
- Display of buttons, menus, icons, input fields
- Formatting and layout on different OS, browser, device combos
- Alignment, size and color of text and graphics
- Scrolling and navigation behaviors
For example, interface tests would validate:
- Buttons are clearly clickable on all viewports
- Dropdown menus open correctly when tapped
- Instructions are readable on all screen sizes
Best practices:
- Design interface mockups and prototypes early for testing
- Check formatting and layout using browser dev tools
- Use automated screenshot diffing tools to catch regressions
- Test key journeys on reference devices covering your target market
I have used Applitools in the past which automated screenshot comparisons across viewports, flagging any differences for our design team to review. This made iterating UI/UX much faster.
Key Takeaways for Mobile App Testers
Thoroughly testing mobile apps across multiple dimensions is critical to minimizing regressions, providing stellar UX, and driving adoption and engagement.
Here are my top recommendations for mobile app testers and QA leads based on 10+ years in the trenches:
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Start testing early on wireframes, prototypes before investing months in coding. Fixing usability issues late can be 100x more expensive!
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Automate ruthlessly – leverage frameworks like Appium to automate regression testing across devices and configurations. This boosts efficiency tremendously.
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Perform security audits – don‘t just rely on developers to ensure security. Execute penetration tests from an attacker mindset.
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Confirm compatibility with target user‘s environments – older OS versions, low-end devices etc. Assumptions can prove very costly!
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Monitor app performance under actual expected load. Use load testing tools to uncover bottlenecks before users do!
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Prioritize UX – a frustrating user experience can tank an app faster than bugs. Observe real users and fix pain points quickly.
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Test continuously, not just before launch – incorporate testing into development cycles from the start till the end.
By considering these best practices, mobile testers and QA teams can maximize app quality and user adoption. Feel free to reach out to discuss if you need help implementing automated, user-centric testing for your mobile apps!