Mobile Testing Interview Questions

Testing tools for Android mobile devices:   

• Robotium
• UI Automator
• Selendroid (Selenium for Android), etc.

Testing tools for iOS mobile devices:

• iOS Driver
• KeepItFunctional, etc.

Testing tools that can be used for both Android and iOS mobile devices:

• Katalon
• Apptim
• 21
• Kobiton
• Appium
• MonkeyTalk
• Ranorex Studio
• EggPlant, etc.

• Mobile Device Testing: Mobile device testing is typically conducted to ensure the quality of the mobile device itself. The process involves testing hardware and software. These tests are generally being conducted to verify the mobile device itself and to test features such as Call, SMS, Memory, Camera, Media Player, inbuilt browsers, etc.   
• Mobile Application Testing: Applications must undergo this whole testing process to survive in today's market. Performance, security, and user interface, and other aspects of the application are also scrutinized (tested) in order to ensure the best possible quality for end-users. This type of testing includes functional, performance, usability, security, load, and other types. Then, you can find out if the targeted application is of high quality, if it is compatible with the device, if it has the right hardware, software, and network connections, etc. 

In terms of how mobile applications are tested, there are two main approaches: manual testing and automated testing.  

• Manual Testing: Manual testing, as its name implies, is a human endeavour, which is primarily concerned with the user experience. It is a time-consuming process as bugs tend to take a long time to appear.
• Automated Testing: In order to avoid time-consuming, costly, and difficult tasks, automated testing is a good option for many repetitive testing tasks, such as regression and performance testing. By using this tool, testers will be able to find errors, defects, or vulnerabilities quickly in newly updated or recently modified applications.

Over the past decades, automation testing has greatly improved the testing process speed and quality. The first step to improving the efficiency of your team is understanding when to make such a switch from manual to automated testing. When deciding whether to use manual or automated testing, you should consider the following factors: 

• Manual Testing:   
  • New functionality has been added to the application.
  • Testing is only needed once or twice, and frequent repetition is not required.
• Automated Testing:
  • A significant amount of regression testing is necessary before every release.
  • Testing by hand is insufficient in labor-intensive situations, such as performance testing, functional testing. However, automated testing does not require much labor because it runs with the aid of tools, scripts, and software that perform predefined actions specified in test cases.

There are two types of automation tools available for testing mobile applications as given below: 

• Object-based mobile testing tools: This approach does not depend on the size of the screen and is mainly used for Android devices. A few examples of Object-based mobile testing tools are Jama solution, Ranorex, etc.
• Image-based mobile testing tools: It generates automation scripts based on screen coordinates. A few examples of Image-based mobile testing tools are RoutinBot, Egg Plant, Sikuli, etc.

Different types of mobile application testing include:  

• Functional Testing: The test determines whether an application is functioning correctly. It aims to ensure that the app's functionality works as expected not like the user interactions as well as transactions that users might perform. It is a type of black-box testing.
• Usability Testing: This type of testing evaluates how intuitive and easy an application is to use, and identifies any bugs to improve the user experience.
• Compatibility Testing: The test determines whether an application whether the application is compatible with different OS (Operating Systems), different network environments, as well as with specific hardware specifications.
• Performance Testing: During this testing, an application is evaluated on how well it performs and behaves under various loads.  In this test, the application is continuously and steadily loaded until it reaches a threshold point (a point beyond which the application cannot withstand the load).
• Installation Testing: Applications undergo this test to ensure that they are properly downloaded, installed, and uninstalled, as well as new updates are handled smoothly.
• Security Testing: Application behaviour under various device permission requests is examined during the test, while the user's data privacy is prioritized.
• Storage Testing: Applications are tested on how well they handle storage-related functions and how they behave when there is no or little memory on the device.

Mobile applications can be divided into three general categories as follows: 

• Native Application: A native application is designed specifically for the operating systems (OS) of mobile phones, such as iOS or Android. They are available on the app stores (Google Play for Android and App Store for iOS) and are easily installed. Mixing and matching - like using an iOS app on a Blackberry phone or a Blackberry app on an Android phone - is not possible. Examples of native applications include Facebook, WhatsApp, etc.

• Web Application: In terms of behavior, web applications are similar to native applications but can be accessed through your mobile browsers such as Chrome, Safari, or Firefox. They are purely web-based applications. Examples of web applications include m.facebook.com, m.gmail.com, etc.

• Hybrid Application: Hybrid applications are composed of both native and web applications. These are web applications that appear and behave just like native applications. Although this type of application can be installed on a device as a native application, it is built as a web application using web technologies (such as HTML, CSS, or JavaScript) and runs on WebView (to display the application on Android) or WkWebView (to display the application on iOS). Examples of hybrid applications include Instagram, Wikipedia, etc.

Simulators and emulators are both virtual devices that look and operate like real phones, but they are not real phones. Emulators mimic the hardware/software and OS of mobile applications to test. In a simulator, the basic behavior of a device is simulated instead of the hardware/OS. In a virtual phone, software mimics the functionality of the real device (apart from a few other functions like the camera). 

Here are the most common problems encountered when performing mobile testing: 

• Conducting tests on multiple operating systems like Android, iOS, Blackberry, Windows, etc., or different versions of an operating system like iOS 4.X, iOS 5.X, BB 4.X, 5.X, and 6.X.
• Test applications' functionality across a wide range of mobile devices, including handsets, smartphones, tablets, and more.
• Screen size fragmentation is also one of the most difficult aspects of mobile testing.
• Testing applications across various mobile networks such as 3G, 4G, and 5G.
• Application types (native, hybrid, and web) require different testing approaches.
• Selecting the appropriate mobile testing tool.

Mobile applications have become a necessity for every business these days because people want everything at their fingertips. When striving for perfection, it's important for developers to evaluate the application regularly to ensure that it meets industry standards. Application testing is one important factor in this process.  

• Before the product or app is released, mobile testing identifies what parts of it work and what needs to be improved, as well as how well an application performs.
• Fixing the issue sooner helps you avoid a bad user experience and a negative rating for your application.
• This ensures that QA (Quality Assurance) matches customer expectations, business goals, and industry best practices.
• By testing the mobile application rigorously, the product team can increase the application's ratings and customer satisfaction, which can lead to additional downloads and valuable referrals.

According to mobile testers, the four most common types of bugs are:  

• Critical bugs: These are the bugs that can cause the system to completely shut down. For example, an operating system crashes when a particular application feature is tested.
• Block bugs: They make it impossible to fix other bugs. For example, unresponsive performance even when the device status is on.
• Major bugs: These are the bugs that could collapse large parts of your application. For example, when a specific function of the application is not working.
• Minor bugs: The bugs in this category cause an application to behave in an unexpected or undesired way, but not enough to cause a system failure. For example, GUI (Graphical User Interface) bugs.

Other kinds of bugs are also found during the testing of mobile applications, for instance:  

• Poor performance of the application.
• Heavy battery usage by the application.
• Non-responsive behavior by the application.

Google Play and App Store offer a variety of tools for developers to measure CPU usages, such as CPU Monitor, CPU Stats, Usemon, and CPU-Z. You can use these to keep track of processes that run on your device.

Following is a list of defect tracking tools used in mobile application testing: 

• Cumin
• Qc
• Rancid
• Rally
• Jira
• Bugzilla
• Trello
• Mantis, etc.

The increasing use of mobile applications in every field makes them more and more appealing to malicious attackers. Because of this, applications should also have strong security, the same as websites, and this is why mobile app penetration testing is conducted. It detects any security flaws in iOS and Android applications. The main objective of this initiative is to increase the security of mobile applications, and APIs, web platforms, and web services they use. It tests all of the elements that contribute to the functioning of the app, such as: 

• Application itself
• APIs (or web services) that exchange and provide data
• Server hosting the API
• Application network interfaces
• User data.

AWS (Amazon Web Service) Device Farm is a mobile application testing service that helps in testing mobile applications across a range of desktop browsers and devices to ensure the quality of applications. To speed up your test suite execution, you can run your tests simultaneously on multiple desktop browsers or real devices. This tool helps you quickly identify issues with your app by generating videos and logs. 

According to the diagram above, AWS tests the application (whether native, hybrid or web) across multiple devices (phones, tablets) to ensure high quality, and shows results in minutes if there are bugs or performance issues.

Here are some iPhone and iPad testing tools:  

• iPhone tester
• Appium
• iPad Peek
• Test Studio,
• Calabash,
• Bugfender, etc.

As the name suggests, cloud-based mobile testing involves the use of an online cloud platform rather than an on-premises environment to test mobile applications. This tool makes all devices available on one platform so that testers connected to a cloud can access them. In this way, developers and QA teams can communicate effectively from all over the world. During the testing process, testers have access to a range of devices, operating systems, screen sizes, network carriers, etc. 

Advantages:  

• Availability without hassle.
• Support for multiple systems and networks.
• In addition to testing applications, the cloud can update and manage them.
• Cost-effective.
• Highly scalable.
• Test scripts can be run simultaneously on multiple devices.

While doing mobile testing on cloud computing, the tester faces the following challenges: 

• In spite of Cloud services being advertised as cost-saving solutions, they can actually cost more.
• Internet connectivity issues
• Since mobile device automation testing is image-based, performing test cases via Cloud computing may be time-consuming and challenging.
• Cloud testing services may not be able to test every new application feature you release, which will result in inadequate coverage.
• Moreover, automation cannot be used outside of the framework.

An automated mobile application testing plan should include the following:  

• Testing scope and objectives
• Selected automation tool
• Required Features to be tested:
  • Performance
  • Security
  • Network
  • Size
  • Battery
  • Memory
• Test cases
• Test strategy
• Person in charge
• Time frame
• Resources required

In mobile applications, A/B testing, also known as split testing or bucket testing, is the practice of testing different user experiences. With A/B testing for mobile applications, audiences are split into two (or more) groups and a variable is tested to see how it affects user behavior. By using this, we can identify and deliver the best possible user experience. In iOS app, it is possible to conduct A/B testing in three steps:   

• Step 1: Configuring a test that prepares two versions of your iOS application (namely A and B) with required test metrics
• Step 2: Testing two of the above iOS versions simultaneously
• Step 3: Analyzing test results and selecting the best version to release

In the above diagram, audience/visitors are split into two groups to check two versions of the application (Variation A and Variation B). Conversion rate (% of visitors to your application who reach their desired goal out of total visitors) of variation A and B is 23% and 11% respectively. Now, you can identify which version is best and deliver the best possible user experience.

The Android testing framework is an open-source framework and one of the most widely used frameworks for testing Android applications. Developers use the Android testing framework to record user interface tests for unit devices and Android devices.  UI (User Interface) testing ensures that your application responds to a user's actions on the device with the correct UI output. There are three segments in the Android testing framework: 

• Application Package: This package contains the target application to be tested.
• Instrumentation Test Runner: As a Test Case Runner, it enables test cases to run/execute on the target application. Essentially, it consists of two parts: an SDK tool for creating tests, and MonkeyRunner, an API tool that allows you to write programs to control Android devices outside of Android code.
• Test Package: This package consists of two parts: test case classes (includes test methods to be performed on target application) and mock objects (include mock data used as sample input for test cases).

Most popular Android test frameworks 

• Poppy
• Detox
• Express
• Calabash
• UI Automator

The following are some of the best common practices for Android testing: 

• When writing the code simultaneously, the developers must also prepare the test cases.
• Detailed documentation and storage of the test cases are essential to reusability.
• Implement continuous integration and run tests as soon as there is a change to the code.
• Avoid rooting your smartphone (which gives you privileged control over the operating system and enables you to change system files, software code, etc.) and using emulators to obtain the most accurate results.

Testing an Android application on a device or emulator is not always easy. It usually takes a lot of effort and time to build test cases. To address this challenge, a robotic testing framework is considered. Using the Robolectric framework, Android tests can be run directly on desktop JVMs (Java Virtual Machines), without the need for a device or emulator. Thus, you don't need to set up anything extra to run Android tests within your development environment. It makes Android application testing faster and more reliable. 

Rather than using classes in Android, Robotetrics used shadow objects. If Robolectric implements a method, this method call is forwarded to the shadow object and it behaves similarly to the Android implementation. In cases where a shadow object does not implement a method, it returns a default value such as null or 0.

Aside from affordability, it is essential to consider the following factors when choosing a test automation tool:  

• Platform compatibility: Make sure the tool is compatible with your current and future target platforms
• Usability of scripts: Object-based tools provide an enhanced level of script usability.
• Jailbreak Requirement: Rooted devices may be incompatible with MDM policies and may not support the latest operating systems so avoid using them.
• Changing source code: Sometimes sharing code is not possible.
• Lead/Update time for New iOS/Android version: How soon can the tool support new iOS/Android versions?

Having secure mobile applications is very important for the business, which in turn, requires testing for the security of all mobile applications. Security testing is therefore considered important testing by testers. Authentication, authorization, data security, hacking vulnerabilities, session management, etc., are all included in mobile application security testing. This test can ensure there aren't any loopholes allowing data to be lost. Testing is meant to identify any potential threats or vulnerabilities that could allow external parties to access private information on the mobile device.

 Testing mobile applications for security include the following: 

• Check if the application supports multiple users without interfering with their data.
• Verifies sensitive data is communicated using a decryption or encryption method.
• Verifies that anyone with unauthorized access to files stored in the app is not accessing them.
• Identify sensitive areas of the application to ensure it does not receive any malicious content.
• Validates an application's resistance to malicious attacks or cyber-attacks and ensures that developers adhere to security practices when programming.

When we don't have enough time for testing and regression is needed, we perform sanity testing. In, sanity testing, the QA engineer confirms that all available menus, functions, and commands are working properly in a product application and project before release. The following criteria should be considered when performing sanity tests on the mobile application:  

• Remember to take into account the installation and uninstallation processes of the application when conducting this test. Verify that the installation and uninstallation go smoothly.
• Identify the device's capabilities in different networks, such as 2G, 3G, 4G, WiFi.
• Ensure the application's functions are thoroughly tested.
• Support interrupt testing - Accept calls as the application runs.
• Testing compatibility features, such as attaching photos from the gallery to messages.
• Assessing how applications perform on another handset/device.
• Test the application by entering invalid credentials and observing the behavior.

A Test Case Runner is a software tool that allows mobile applications to be tested. In essence, runners act as an environment that represents both the device and the end-users. A near-exact simulation of the user environment is generated and the application's functionalities are tested just as if a human were using the device. It helps determine whether the application is ready for launch. Commonly called an instrumentation test runner, it runs test cases on an application smoothly. 

The mobile usability testing process involves evaluating mobile products according to how they are used by end-users, so the goal is to make them as user-friendly as possible. It can assist you in evaluating the functionality of your mobile app and also ensure that your users have an easy time navigating your app. Mobile usability testing entails doing research and finding problems early on. In order to determine the efficiency of the target audience, it evaluates the application based on the following criteria:  

• Effectiveness
• Satisfaction

It is very important to get usability testing in place from the initial stage of application design, and this should not be done only when the application is completed. Usability testing requires excessive involvement of users, and output can affect application design, which is very difficult to change in later stages of the project. 

A popular open-source testing tool for mobile applications is Appium, which automates tests for platforms like Android, iOS, and Windows. It is used to automate the testing of native, hybrid, and web applications. This tool is quite popular due to its availability, free nature, low memory consumption and integration with other external applications such as Selenium WebDriver and Selenium Grid. The tool is cross-platform, meaning the same test can be run on multiple platforms. Appium can test multiple devices simultaneously. 

Appium also offers the following additional advantages to testers and developers: 

• Executes multiple test scripts simultaneously.
• Includes a tool for recording test cases and a playback tool for replaying those recordings.
• Allows testing various elements simultaneously (e.g., emulators, real devices, and simulators).
• Cloud-based testing is supported using Testdriod.
• Supported by an active community (Google group) that enables troubleshooting to be done more quickly and easily.

Test scenarios are simple sets of functionalities (detailed documents of test cases) that can be automated or manually tested in a mobile application or website. In addition to providing insight into the positive and negative characteristics of an application or website, test scenarios are often very useful to the testing team.  Because testers test applications from the user's perspective, they must put themselves in the position of the user during a test scenario. 

Advantages:

• Help developers understand how mobile applications really work
• Ensure that the end-to-end functionality of the app under test works as expected.
• The testing team will be able to understand what needs to be tested with the aid of an effective test scenario.

One of the most challenging aspects of app testing is writing test scenarios for mobile applications. However, scenario-based testing is the best method for testing complicated systems, so be sure to keep these tips in mind when preparing mobile application testing scenarios.  

• Examine the Requirement Document, including the BRS (Business Requirement Specification), SRS (Software Requirement Specification), as well as the FRS (Functional Requirement Specification) pertaining to the SUT (System Under Test). 
• Design simple test scenarios rather than complex ones. Keep them concise and simple, so they are easy to understand. 
• Generate test scenarios that cover all possible features of the target application. Users and business flows involved in the operation of the application/website must be covered by these scenarios. 
• Put an emphasis on project methodology. 
• Identify the priorities of your customers and devise test scenarios accordingly. 
• Keep an eye on the expected outcome. 

Some of the top mobile application testing scenarios include: 

• Install and launch the application before using it.
• Ensure that the application is adaptable to the screen of the mobile device and that all menus on the app are working.
• Inspect the readability and clarity of the text in the app.
• Check if the display of the application can be adjusted to various display modes (landscape/portrait).
• Be sure that the application does not interfere with other applications on the device.
• Ensure the back key on the play screen will take you back to the application's start-up screen.
• When the device is resumed from inactive mode or the lock screen, make sure the application still functions as intended.
• Applications should remind users to save any changes they make to settings before moving on to other activities.
• As soon as the user attempts to enter text, the on-screen keyboard should appear.
• Check that the application functions as intended when the "battery low" notification appears.
• Check how the application performs over the various internet network types, such as 1G, 2G, 3G, and 4G.
• Applications should be adaptable to different mobile platforms or operating systems, including Android, iOS, Microsoft, etc.
• See how the application behaves at different levels of battery and temperature, and many more.

Mobile Functional Testing means testing the functions of mobile applications, such as user interactions and transactions. Functional testing is performed by mobile application developers to ensure application quality, meet user expectations, and reduce the risk of errors in mobile applications. The most common scenarios in functional testing include: 

• Verify that all required mandatory fields work as intended.
• Every time an application starts/stops, make sure the application works correctly.
• If the app is running, check whether SMS can be stored, processed, and received.
• Check if the device can perform multitasking functions when necessary while the application is running.
• Verify that the application provides access to social network features, such as sharing, posting, and navigation.
• Check that the application is configured to support the page scrolling scenarios.
• Verify that navigation between relevant modules is in accordance with the requirements.
• Check to ensure that the user receives an appropriate error message, such as "Network error".
• Ensure that the installed application does not consume the memory of other applications and that it enables other applications to perform satisfactorily.
• If the system crashes or the application crashes, verify that it resumes from the last operation.
• Ensure that the user has access to the required resources to install the application smoothly and that it will not lead to significant errors.
• Testing the performance of the application in all versions of Mobile, including 2G, 3G, and 4G.

During performance testing, an application is evaluated on how well it performs and behaves under various loads. In this test, the application is continuously and steadily loaded until it reaches a threshold point (a point beyond which the application cannot withstand the load). This ensures that the application performs as expected under certain conditions like when large numbers of users access it or when a key infrastructure component such as a database server is eliminated. The most common scenarios in performance testing include: 

• Test the application under various load conditions to determine if it performs as expected.
• Check the current network coverage for its ability to support maximum, average, and minimum user levels.
• Ensure that client-server configurations provide optimal levels of performance.
• Identify the application and infrastructure bottlenecks that affect the app's performance.
• Analyze whether the hardware and/or product can cope with the projected load volumes.
• Evaluation of the battery life's ability to support the expected load volumes.
• Check the performance of the application when it's switched from a 2G/3G network to WiFi or vice versa.
• Make sure that battery consumption, memory leakage, GPS, and camera performance are within permissible limits.
• Validate the app's endurance whenever there is a high user load.

Conclusion

The global digital transformation is leading to a rapid increase in mobile usage. Everyday life is inextricably linked to our mobile phones; life without one is difficult to imagine. With consumer demand increasing, nearly all software applications now have mobile applications, so businesses have to put more emphasis on mobile testing. Due to the demand for innovative mobile solutions delivered quickly, the need for mobile testers has grown greatly over the years. In light of the rapidly expanding mobile industry, there are many opportunities in mobile testing. This blog includes basic and advanced mobile testing interview questions and answers for both freshers and experienced mobile testers. This set of questions covers all the basics of mobile testing and demonstrates your familiarity with the topic.

Additional Interview Resources

• https://www.interviewbit.com/software-testing-interview-questions/
• https://www.interviewbit.com/functional-testing-interview-questions/
• https://www.interviewbit.com/appium-interview-questions/
• https://www.interviewbit.com/sdet-interview-questions/
• https://www.interviewbit.com/performance-testing-interview-questions/
• https://www.interviewbit.com/ionic-interview-questions/
• https://www.interviewbit.com/technical-interview-questions/
• https://www.interviewbit.com/blog/testing-tools/
• https://www.scaler.com/topics/mobile-operating-system/