Compatibility Testing

In this tutorial, we are going to study Compatibility Testing. Compatibility testing is a type of non-functional software testing which focuses on testing the compatibility of the product with other systems and devices. We have briefly discussed compatibility testing in the Non-Functional Testing tutorial, and there we got some idea of what exactly compatibility testing is.

Here, we will cover terms and information related to compatibility testing, such as what compatibility testing is, the need for compatibility testing, parameters of compatibility testing, types of compatibility testing, compatibility testing tools, advantages and disadvantages of compatibility testing, and more.

Let's begin with what compatibility testing is.

What is Compatibility Testing?

A type of non-functional testing that tests the software’s compatibility with other devices, applications, operating systems, networks, and mobile devices is known as Compatibility testing. In other words, it is used to verify that the application must be compatible with multiple software and hardware devices, web browsers, operating systems, databases, etc. It ensures that the application should meet all the compatibility checks and delivers the best user experience to its users. It also tests the application's compatibility with max and min configurations.

Compatibility testing is generally performed when the system is in stable condition. Through compatibility testing, we can also test the different versions of the same application. It is further classified into various types of compatibility testing, which we will discuss later in this tutorial.

Why do we need Compatibility Testing?

Like other testing types, compatibility testing is also essential in the software testing process as it verifies the compatibility of the system with other devices, operating systems, browsers, etc., when the developed system is stable. Compatibility testing is mainly performed to check whether the user can work on a system with different browsers, operating systems, etc. It is necessary to get 100% customer satisfaction so customers can use the application easily. It ensures that the product will work on all possible combinations of hardware and software devices, operating systems, browsers, networks, and more, as desired by the users.

Let us understand the need for compatibility testing with the help of an example:

Example: An e-commerce application is developed, and the stable version of it is moved into production. Multiple users are accessing the application on different operating systems, browsers, and with various networks. Some users are facing compatibility issues, such as the application not working on 'Microsoft Edge' but working on 'Google Chrome'. In such cases, we must perform compatibility tests which helps us to deliver a good product with excellent customer experience and satisfaction.

Parameters covered under Compatibility Testing

As discussed above, compatibility testing is used to test the compatibility of the product. To deliver a stable and compatible product, we need to cover some parameters for efficiently performing the compatibility testing. These parameters help us to enhance the productivity and quality of the product.

Following are the parameters/ attributes covered under usability testing:

• Hardware – While performing compatibility tests, hardware compatibility should be tested properly to ensure that the developed system is compatible enough to work with various hardware configurations uniformly in the desired manner.
• Software – Testing the system’s compatibility with other software systems is another parameter covered under compatibility testing. It ensures that the developed product must be compatible with other software in the system without creating any problems. For example, we can open a document with MS Word, PDF reader, Notepad, etc.
• Network – Another compatibility testing parameter is Network. We validate the product on different networks, such as 3G, 4G, 5G, Wi-Fi, etc., for various network parameters like operating speed, capacity, bandwidth, and more.
• Software Versions – Another compatibility testing parameter is Version. In this parameter, the compatibility of the system with its older and newer versions is tested. For this parameter, we have two types of compatibility testing, i.e., Backward Compatibility Testing (older) and Forward Compatibility Testing (Newer).
• Operating System – Another compatibility testing parameter is Operating System. In this parameter, we test the system’s compatibility with various operating systems such as Windows, Mac, Linux, Unix, etc.
• Browser – Another compatibility testing parameter is Browser. In this parameter, we test the system's compatibility with different web browsers available in the market, such as Google Chrome, Mozilla Firefox, Internet Explorer, Microsoft Edge, Opera, Safari, and more.
• Mobile – Another compatibility testing parameter is Mobile. In this parameter, we test the system’s compatibility with mobile platforms of different brands having different operating systems, such as Android (Samsung, One Plus, etc.) and iOS (iPhone).
• Device – Another compatibility testing parameter is the Device. In this parameter, we validate the product's compatibility with various external devices such as USB, pen drives, scanners, printers, speakers, Bluetooth, and more.

Types of Compatibility Testing

There are different types of compatibility testing based on the compatibility parameters present in software testing, which are mentioned below:

1. Hardware Compatibility Testing – In this type of compatibility testing, we focus on validating the compatibility of the system with hardware configurations such as RAM, ROM, Hard Disk, Processor, Memory Cards, and more. The product should be compatible with all the hardware configurations present in the system and maintains uniformity over different hardware devices.
2. Software Compatibility Testing – In this type of compatibility testing, we focus on validating the compatibility of the product with other software devices present in the system. In other words, it checks whether the developed product is compatible with other software of the system without discrepancies.
3. Operating System Compatibility Testing – In this type of compatibility testing, we focus on validating the product’s compatibility with different operating systems such as Mac OS, Linux, Unix, Windows, etc.
4. Network Compatibility Testing – In this type of compatibility testing, we focus on validating the product’s compatibility on different networks, such as 2g, 3g, 4g, 5g, and more. It ensures that the product is consistent across various networks.
5. Browser Compatibility Testing – In this type of compatibility testing, we focus on validating the product’s compatibility with different browsers such as Chrome, IE, Microsoft Edge, Firefox, Safari, and more. It is also known as cross-browser compatibility testing, and it ensures that the product is uniformly behaving across all browsers.
6. Mobile Compatibility Testing – In this type of compatibility testing, we focus on validating the product's compatibility with various mobile devices and platforms, such as Android and iOS. It checks whether the product is performing consistently across different mobile phones with operating systems.
7. Device Compatibility Testing – In this type of compatibility testing, we focus on validating the product’s compatibility with several other devices, such as UBS port, scanners, printers, Bluetooth, etc., on ensuring the system is stable with all other devices.
8. Version Compatibility Testing – In this type of compatibility testing, we focus on validating the product’s compatibility with different versions of the product (older and newer). It ensures that all the versions and variants of the product are stable and compatible with other parameters. Version compatibility testing is further divided into two categories, as mentioned below:
   • Forward Compatibility Testing – In this type of version compatibility testing, we validate the product’s (software/application/website) compatibility and behaviour with the newer or latest versions of the product. We can find it challenging as the changes and modifications that will be made to the product's version is unknown. An example of forward compatibility testing is different versions of MS Word:
     MS Word 2010 (version 14.0) à MS Word 2013 (version 15.0) à MS Word 2016 (version 16.0) à MS Word 2021 (version 16.0).
   • Backward Compatibility Testing – In this version compatibility testing, we validate the product's (software/application/website) compatibility and behaviour with their previous or older versions of the product. It is easier than forward compatibility testing as we can easily predict and observe the changes in the earlier versions. It is mainly used when some users operate the product on old devices and systems. It is also known as Downward Compatibility testing. An example of backward compatibility testing is different versions of MS Word:
     MS Word 2010 (version 14.0) ß MS Word 2013 (version 15.0) ß MS Word 2016 (version 16.0) ß MS Word 2021 (version 16.0).

Compatibility Testing Process

Like other software testing, the compatibility testing process follows procedures and steps to perform testing efficiently. Below mentioned is the step-by-step approach for performing compatibility testing.

• The first step is to get the requirements (both functional and non-functional requirements) from the client or customer for developing a product. The testing team will study and understand the requirements of the product.
• Once the product is developed and all functional tests are completed, the testing team will perform non-functional tests.
• Testers start with setting up the environment and data for different compatibility testing types, which includes selecting the appropriate tool for testing, accurate test data, and more. They also gather information about other browsers, hardware, software, devices, etc., to understand the application's expected behaviour and perform successful compatibility testing. Different environments are required for different types of compatibility testing.
• Once the test environment setup is done, testers will start executing tests and documenting the test results. The end-to-end workflow of the application/website is tested for its stability and compatibility across various platforms. If any of the test cases gets failed, bugs will be reported to the appropriate developer for a fix. Retesting is done after the bugs are fixed by the development team.
• The last step of the testing process is to collect and gather all the test reports and results and document them as evidence for clients and customers.

Common Compatibility Testing Issues

While performing compatibility testing, we may encounter some bugs and issues in the system. Usually, most of the compatibility bugs are related to the UI or GUI of the product. Some of the most common compatibility issues are mentioned below:

• Look and feel issues – These consist of problems which are related to the appearance and functionality of the user interface of an application or website, such as changes/modifications in a website that can behave inconsistently in different browsers. For example, text fields on a webpage or website are consistent and organized well on one browser, i.e., Google Chrome, whereas, on Internet Explorer, it seems a bit scattered and unorganized.
• CSS Style and colour issues/ validation issues – One of the most common issues encountered in cross-browser compatibility testing is CSS style and colour issues. In this issue, there is some data mismatch with the browser or the code is not appropriately written in HTML or CSS. Therefore, different browsers read and handle the code differently.
• Alignment issues – In this issue, the elements of a webpage are not aligned in a proper format. For example, a webpage consists of 5 text fields which are improperly aligned, such as three fields being left-aligned and the other two being slightly right-aligned.
• Content-related issues – This type of issue occurs when the content of a webpage seems to be overlapped. Simply put, when an attribute or text overlaps another attribute or text line, it is known as an overlapping or content-related issue. It can happen when someone tries to open an application or website with different browsers across various platforms.

Compatibility Testing Tools

We can perform compatibility testing manually as well as automatically. However, it is better to go with automated compatibility testing as all non-functional testing types are more successful through automation. Some of the most popular compatibility testing tools are mentioned below:

1. LambdaTest - It is one of the most powerful cloud-based platforms mainly used for cross-browser compatibility testing of websites and web applications. LambdaTest can also be used for Accessibility testing, Responsive Testing, and Localization Testing. It offers us to test all websites and web applications consistently over more than 2000 desktop and mobile web browsers, device emulators, and operating systems with manual, automated, and visual testing. It also provides a feature of one-click defect reporting, i.e., a tester can directly log a bug from the LambdaTest tool to different defect management tools such as JIRA, Mantis, GitHub, Trello, etc.
2. TestComplete – It is a licensed automation tool mainly used for performing compatibility and functional testing tests for mobile, desktop, and web applications. TestComplete is developed by SmartBear software which works on GUI functional testing. It supports features such as recording and playback, scripting and manual modes for tests with built-in keywords. It also supports several scripting languages like Python, JavaScript, VBScript, Delphi, etc., and different testing techniques such as data-driven testing, keyword-driven testing, distributed testing, and regression testing.
3. Ranorex Studios – It is a testing solution for the automation testing of mobile, web, and desktop applications. It also helps in shortening the regression testing cycle. It is mainly used for GUI testing and compatibility testing with data-driven and keyword-driven testing frameworks. It can also integrate with other tools like Jira, Jenkins, Git, Travis CI, TestRail, etc.
4. Virtual Desktops – One of the most valuable and convenient testing platforms for operating system compatibility testing is virtual desktops. It is a technology tool used to host one desktop screen/operating system on the centralized server in a data centre, so the user or tester can watch and observe what is happening in the system, how the system is behaving, etc. In simple words, it is used to run the application/software as a virtual machine in multiple operating systems at the same time. There are numerous Virtual Desktop Infrastructure (VDI) tools available in the market for compatibility testing, such as Amazon Workspaces, Citrix Virtual Apps and Desktops, Red Hat Virtualization, VMWare Horizon Cloud, Vagrant, Parallel RAS, and more.
5. Browsera – It is one of the best tools for cross-browser compatibility testing and is mainly used for identifying the scripting and layout errors of the website and application. It is an automated testing tool which tests multiple web pages simultaneously and generates a test report once the test execution is completed. The primary purpose of Browsera is to validate and compare the output of each browser and identify the differences in the web pages and fix them. Some of the main features of Browsera are identifying layout problems and JavaScript errors, no installation required, supporting dynamic page testing, HTTP authentications, application-based logins, etc.
6. BrowserStack – It is one of the most popular and reliable live and browser testing tools available in the market. Like other compatibility testing tools, it allows us to test our application or website over 2000+ real devices and browsers. It also helps in instant access to debugging and troubleshooting the product. In general, it is a cross-browser testing tool that allows us to test the websites and mobile applications compatibility over multiple browsers and platforms. BrowserStack is available with different pricing plans and also provides a free trial. It also supports Selenium testing.
7. TestingBot – It is a commercial cross-browser testing tool which can be used for both manual and automation testing. It executes and runs a test on more than 3800 leading browsers (Chrome, Safari, Firefox, Edge, etc.), devices, and operating systems (Windows, Linux, and macOS) and also mobile applications on Android and iOS mobile devices. It is known explicitly for executing its most extensive cloud-based Selenium grids on the web.
8. CrossBrowserTesting (BitBar) – BitBar, formerly known as CrossBrowserTesting, was developed by the SmartBear organization. It is one of the most common and reliable cloud-based testing solutions mainly used for cross-browser compatibility testing. It offers us to perform live testing, visual testing, manual testing, and automated testing on more than 2050 browsers. It helps to scale the testing process by increasing the test coverage and reducing the test execution time with the help of automated tests. It is available with different pricing plans, along with a free trial for seven days. It also supports Selenium and Appium test scripts.
9. SauceLabs – One of the leading compatibility testing tools mainly used for cross-browser testing for developers and testers is the SauceLabs testing tool. It is famous for its world's largest cloud-based platform, which offers automated, live, and continuous testing for mobile and web applications. It provides over 800 combinations of browsers with each version (Chrome, Internet Explorer, Opera, Safari, etc.) and operating systems (Android, iOS, Windows, Linux, Mac OS, etc.) for testing. The objective of SauceLabs is to provide complete test coverage, scalability, quality, and analytics to deliver a flawless user experience. SauceLabs is developed by the founders of Selenium and is available in both open-source and commercial versions.
10. Browserling – Like SauceLabs, Browserling is also a leading, interactive, and easy-to-use cross-browser testing tool. One of the significant features of Browserling is that it allows us to have live interaction with different browsers. It usually links us with real browsers on real machines to provide a real testing experience, just like we have installed it on our system. It supports various browser extensions such as Chrome, Firefox, Safari, etc. It is available in both free and paid versions in the market.

Advantages of Compatibility testing

The following are the advantages of compatibility testing:

• It tests the compatibility of the developed software/ application with other software/ hardware, browsers, operating systems, networks, and more when the system is stable.
• It reduces the cost of customer support and services and focuses on attracting customers by providing customer satisfaction.
• Compatibility testing helps a product to avoid customer complaints and issues related to the compatibility of the product.
• It provides a great customer experience.
• Apart from compatibility, it also checks the stability, usability, and scalability of the product.

Disadvantages of Compatibility testing

The following are the disadvantages of compatibility testing:

• Compatibility testing requires a wide range of platforms for testing a product. For example, while performing browser compatibility testing, the application must be tested on every possible browser available in the market. Although, most of the cross-browser testing tools offers 2000+ browsers and operating system to test the application and website. However, it is very time-consuming to test the product on each browser, even if it needs to be updated.
• Sometimes, compatibility testing becomes very expensive as it requires a lot of staff and resources, purchasing hardware and software for testing, other devices, and providing additional facilities to deliver a highly compatible product in all forms.