Getting Started With Visual Regression Testing Using Selenium

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These days, people of all ages are becoming more and more dependent on the Internet. They all desire visually appealing designs and a positive user experience. Therefore, engaging layouts and designs are essential for user engagement; also, built websites and applications need to be of similar quality across all platforms.

To ensure that the website or web app is user-friendly and visually appealing, visual regression testing is required. Visual regression testing is crucial to ensuring that the web app always remains flawless and that there are no visual imperfections after adding or correcting new UI features.

Different design elements, such as images, pages, colors, typefaces, and other visual components of a website or application, have an important impact on the user experience; as a result, they must be accurate for the layout to be considered appropriate.

When a layout is said to be correct, it means that each element’s placement on the screen is accurate. The elements must also stand out from one another and not overlap. They must also be visible rather than hidden.

It’s critical to identify visual flaws that lead to inaccurate interface displays because they can seriously impair an app’s usability and accessibility and degrade the user experience.

In this post, we’ll go over everything you need to know about visual regression testing with Selenium. We’ll start by discussing what visual regression testing is, why it is important, why it should be done using Selenium, how it identifies issues,  its benefits and drawbacks, and some recommended practices to make it more effective.

Visual regression testing

An application’s or website’s user interface (UI) accuracy is checked after any code changes through a method known as visual regression testing, sometimes known as user interface (UI) testing. Since they will contribute to a user’s first impressions, they are the most obvious to users. Visual regression testing makes sure that any style issues don’t appear when the application is changed in any way. The application’s prior degree of visual excellence should be maintained.

Regression testing is a type of application testing that ensures previously designed and tested applications continue to function correctly after updates or changes to the source code are performed. Regression testing verifies that no new bugs have been added as a result of application changes. Before a user views the website, it seeks to identify any issues, potential or otherwise.

The visual components of the web pages are crucial and fundamental to how the user interacts with the application. Visual regression tests emphasize how the user will experience the application’s final user interface.

The purpose of visual regression testing is to identify visual “bugs” such as misplaced buttons, overlaying text or images, partially visible elements, responsive layout and rendering issues, etc. Screenshots of the current user interface are created, examined, and compared to the baseline during visual regression testing.

So, the objective of visual regression testing is to look at previous variations. It confirms that despite code modifications, the web page continues to render as intended in different browsers.

Importance of visual regression testing

User experience (UX) and user interface (UI) are now both very important. No matter how well the application works, the user will only find it useful if they have a good user interface and experience. Maximizing revenue requires a positive user experience. To maintain user engagement, the user interface must not only be functional but also offer the best experience to the user.

Visual regression testing is important because users will leave a website or remove an app if the visual interface, such as the location, size, and form of each piece, has been designed incorrectly and makes a site or app difficult to read or use.

Visual regression testing also looks for ads that cover the page and hide text or block buttons and links. Compatibility problems between browsers, screen sizes, and operating systems may also contribute to this. The way that pixels are coded and displayed can vary depending on the device, screen size, resolution, operating system, and browser used.

Visual design affects the user experience in several ways. For instance-

• Strong visuals help establish credibility and trust.
• Improves the brand’s reputation.
• Enhances the overall balance of the image on the screen.
• Motivates users to act.
• Persuades the eye to focus on particular elements of the page.

Why use Selenium for regression testing

The number of applications being tested manually and automatically has increased significantly in recent years. Due to its numerous useful features and services, Selenium is currently the most popular testing tool for web testing on desktop and mobile devices. It is an open-source suite of tools that supports numerous languages, including Java, C#, Javascript, etc.

A wide range of tests, including UI testing, sanity testing, and regression testing, may be run with Selenium. Regression testing with Selenium enables developers to identify issues with their web applications before users are impacted. Such tests assist developers in strategically changing code and adding new functionality.

Testers can focus on resolving problems and conducting more challenging tests by automating regression testing using Selenium. Additionally, Selenium automation testing makes it possible to complete the development process quickly and effectively. Teams can quickly and efficiently uncover defects and issues in their web tests with automated Selenium regression testing. Given its widespread popularity, it makes sense for testers to attempt Selenium-based automated visual regression testing.

How do visual regression tests function?

The purpose of visual regression testing tools is to simply verify that each UI element is displayed in the appropriate size, color, and placement and that no components are hidden or overlap. It ensures that even after numerous upgrades, the app will run without a hitch.

So, to perform visual regression testing, one needs a tool like Selenium that mimics user behavior. Throughout the testing process, Selenium takes screenshots, which are then compared with the original screenshot taken as a baseline. These screenshots aid in locating potential visual bugs that may have crept into the application or have already developed as a result of a regression.

Every time a change is noted, a screenshot is taken to show the variations from the starting point. Reviewers then decide whether the problems are due to coding errors that developers must address or to an issue with ad integration that needs to be resolved. The test will be regarded as successful if the comparison of the screenshots reveals no unexpected discrepancies and the web page continues to render as expected across different browsers even after coding changes.

Benefits of visual regression testing

As we have already mentioned, visual regression tests have a lot of potential because they enable evaluating applications using a visual method that is not possible with other types of tests. By doing so, it contributes to expanding the scope of the already-existing automated tests and achieving a crucial level of coverage against errors that would otherwise go undetected yet have a direct impact on the user experience. By including these tests in practice, it will be possible to identify visual errors as soon as possible.

The downsides of visual regression testing

Regression testing fits with the saying that “good things come with bad things.”  Visual regression testing does have some drawbacks, despite how effective it can be. Therefore, it’s also crucial to consider some of its drawbacks before putting it into practice.

Increases maintenance costs since screenshots of web interfaces must be maintained while accounting for all of their numerous variations, including those caused by using various browsers, devices, operating systems, and other aspects.

False positive results might come from image comparisons. Because failures that don’t match up with errors are being examined, this could produce incorrect results and be time-wasting.

Despite these drawbacks, there are some effective methods for carrying out visual regression testing. If taken into consideration, they will aid in finding a fast solution to the issue of identifying visual mistakes.

By putting the below-mentioned advice into practice, it will also be feasible to maximize test findings, save maintenance expenses, and decrease the likelihood of experiencing false positives.

Tips for performing visual regression tests

To acquire the most useful findings from visual regression testing, focus on the application interfaces (where the most important or urgent issues are). This will assist in reducing the number of images in each case so that only the most crucial ones are highlighted.

Pixel-by-pixel comparisons should never be made because they are more likely to fail. Use other comparison logic kinds that are better suited to the demands, such as layout, content, etc. This will make it easier to get more reliable and predictable results.

Consider baselines for the devices on which the application is most frequently used, as well as for the most popular browsers on each of those devices. This will assist in focusing on the key variations.

Utilize platform to perform visual regression testing

Visual regression testing is becoming increasingly significant in continuous integration techniques used today. Visual regression testing verifies that the website’s visual elements, such as styles, layouts, alignments, etc., are accurate following the addition or correction of new UI features.

Furthermore, there are currently a variety of operating systems, web browsers, screen resolutions, and devices available. Testing for various devices, browsers, and operating systems is crucial to ensuring the user interface appears flawless across all potential setups and that users are receiving the same experience.

As a result, testing teams require a platform that enables visual regression testing as well as other testing types, including UI and API testing across a variety of devices, browsers, and operating systems.

A good visual regression testing platform should also offer automated visual testing, visual comparison capabilities, integration with other testing frameworks, cross browser testing, cloud testing, reporting and analytics features, collaboration tools, etc. Teams can manage application quality better with such a platform.

One such cloud-based AI-powered test orchestration and execution platform, comes with all the functionalities listed above and offers smart visual testing features to find visual UI regression errors. Additionally, it offers access to a cloud of more than 3000 real devices, browsers, and operating system combinations so that testing for both web and mobile applications can be done manually and automatically.

The visual testing platform enables teams to assess discrepancies in two image layouts. With the aid of smart testing, testers can test a web application visually by taking screenshots, comparing them to baselines, and looking for visual flaws in the UI’s text, layout, color, size, padding, element position, etc. Teams can do this to minimize resources and concentrate on determining what is most important.

It supports several automation frameworks, including Selenium and Cypress to execute automated visual testing in numerous programming languages, such as Java, Node.js, and C#, and to provide visually appealing apps,  With reliable regression testing, it offers a strong visual testing algorithm that minimizes false failures and delivers quick, and precise findings.

Its advanced parallel testing capabilities also make it possible to run large-scale executions of complex test suites, significantly reducing test execution time. Additionally, it can be smoothly connected with source code management systems, CI/CD pipelines, and tools like Jenkins, GitLab, and Bamboo to add visual tests to every code commit.

Other standout features of include-

• Assistance with geolocation testing, cross-browser testing, and other testing.
• The screenshot testing feature takes full-page screenshots, which makes it easy to track out visual errors and quickly identify visual defects.
• Screenshot tests are available for the majority of desktop and well-known mobile devices. When testing dynamic responsiveness across desktop browsers and mobile orientations, testers can mix and match the browser resolution.
• The ability to quickly select test results and spot visual issues. Additionally, testers can troubleshoot or fix visual flaws during a live test.
• Jira and other bug reporting tool integrations for enhanced outcomes and reporting.

Conclusion

We can conclude that an excellent user interface and experience depend on a clean, visually pleasing website. Even the slightest user interface distortion can be annoying and harmful to an organization’s revenue at worst.

Therefore, visual regression testing becomes essential as the application evolves from version to version and proceeds across browsers to guarantee that the new modifications do not mess up the layout. This will improve the user experience because a user may consider an appealing layout to be easier to use.