What is Compatibility Testing? Forward & Backward Testing


In simple terms, compatibility is the state in which two different things can coexist without conflicting. In real world, milk is compatible with water, oil and water are not compatible with each other.

Compatibility Testing

Compatibility testing is sub-category of software testing performed to determine whether the software under test can function on different hardware, operating systems, applications, network environments and mobile devices. It is a non-functional testing and is performed only after the software becomes stable.

The main objective of compatibility testing is to check the functionality of the software on different software, hardware, networks, etc. It is essential to software development and implementation as it avoids future problems in terms of compatibility.

Types of Compatibility Tests

  • Hardware − It determines whether the software is compatible with various hardware configurations or not.

  • Software − It determines whether the developed software is compatible with various other software or not, e.g., MS WORD must be compatible with other software such as MS Outlook, MS Excel, etc.

  • Operating Systems − It determines whether the software under test is compatible with various OS like Windows, Unix, Mac OS, etc.

  • Network − It checks the performance of the software in a network in terms of various parameters such as bandwidth, operating speed, and capacity. It also tests the software under test in different networks with all parameters that were specified earlier.

  • Browser − It tests the compatibility of a website under test with various browsers, e.g., Firefox, Chrome, Internet Explorer, etc.

  • Devices − It tests the compatibility of the software under test with various devices such as USB port, printer, scanner, Bluetooth, etc.

  • Mobile − It tests whether the software under test is compatible with various mobile platforms such as Android, iOS, etc.

  • Software Versions − It determines whether the software under test is compatible various software versions. For example, testing whether Microsoft Windows is compatible with Windows 8.

Types of Compatibility Testing

  • Backward Compatibility Testing − This testing is performed to check the behaviour and compatibility of the hardware or software with their older versions. This testing is predictable because all the changes from the older versions are known.

  • Forward Compatibility Testing − This process is used to check the behaviour and compatibility of the software or hardware with their recent or new versions. It is difficult to predict forward compatibility testing because the changes made in the newer versions are unknown.

Tools for Compatibility Testing

  • BrowserStack − This tool enables software engineers test websites and mobile applications in different browsers and platforms. It provides tools such Live, Automate, App Live, and App Automate, using which the cost can be maintained. These tools also help reduce time, expenditure, and maintenance costs.

  • Virtual Desktops − This tool is used to test the software in various operating systems as virtual machines. Multiple systems can be connected and their results can be compared.

  • LambdaTest − This open-source tool is used to test web applications on any mobile browser and desktop browser. It offers a screenshot feature which helps take full page screenshot of web pages. This tool lets test applications on real browsers, and provides a large number of mobile and desktop browsers to verify the compatibility of the application.

  • BrowseEMAII − This tool is used to run applications on different OS, like Linux, Windows, macOS, etc. BrowseEMAII is a cross-browser testing tool used to test applications on almost all mobile browsers and desktop. It can be directly used on local machine in local network.

  • TestingBot − This tool is used to test the application on various browsers such as Firefox, Google Chrome, Microsoft Edge, Internet Explorer, Safari, etc. In this tool, the screenshots from multiple browsers and platforms can be compared and the responsive layout of the application can also be tested. It offers a number of browser versions for automation testing.

How to do Compatibility Testing

  • The preliminary stage defines the set of environments the software under test is expected to run on.

  • The tester or the testing team must possess proper knowledge and skills of the software or hardware to understand the expected behaviour of the software in different configurations.

  • The environment must be established to test with various platforms, devices, networks to verify whether the software can run well under various configurations.

  • Report the bugs discovered during testing. Resolve the defects and other problems. Conduct the test again to confirm that all the defects have been fixed.

Example of Compatibility Testing

Consider that you have created a complex excel sheet to track the project, resources, expenditure, etc. using Excel 2000. You then update your MS Office 2000 to MS Office 2010. It is expected that the functions working on MS Office 2000 still work on the update version. That is, the assets you created with the older version should work on the updated version. But, if these assets do not support the updated version, then an appropriate migration path should be provided to you so that you can migrate easily from the older version to the current one.

Need of Compatibility Testing

  • To make sure that customer(s) is(are) completely satisfied.

  • To provide services across various platforms.

  • To detect bugs or defects while the software is in development phase.

Compatibility Testing Issue

These issues arise in a single platform, and not in another platform. The compatibility issues are commonly UI (user interface) issues.

  • Alignment issue

  • Overlap issue

  • Scattered issue

  • Look and Feel issue

Alignment issue

These issues are those in which the elements of the web page is not properly aligned in an appropriate format.

Overlap issue

It may happen that one attribute overlaps with another. This may occur while trying to open the application on different platforms, browsers, environments, etc.

Scattered issue

These issues arise while performing compatibility testing, the application is not compatible with multiple browsers, platforms.

Compatibility issue

This issue occurs when the application runs well in all operating system but not in a specific operating system. The reason is a program written by the application developer works fine in all platforms, but not in a specific platform.

Functionality issue

This issue occurs when a feature of the application is not working as expected in all operating systems or platforms. It is also referred to as functionality defect issue.

Advantages of Compatibility Testing

  • Compatibility testing helps meet customer requirements and avoid any complaints in the future.

  • The feedback provided in the testing phase improves the development process.

  • It not only checks compatibility, but also scalability, usability and stability of the software under test.

  • It ensures that all the prerequisites are met and agreed upon by the developer and the customer.

  • It helps gain success in business operations.

  • It also helps improve the reputation and goodwill of the company.

Compatibility testing helps ensure the software can work under different configurations and its compatibility with the customer’s environment. This testing reduces the overall error of the software. It is comparatively inexpensive and is like a boon that ensures success of the software.