Exploring Visual Regression Testing in Cloud-Based Automation

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As the demand for faster software development and deployment boosts, testing has become an integral part of the software development life cycle. In testing, it is vital to guarantee that the software acts as envisioned across different environments and browsers. Traditional testing methods, such as functional and unit testing, may not invariably capture the visual modifications that can occur in a web application. To address this, Visual regression testing has become a popular method for ensuring that the visual aspects of an application remain consistent across different versions.

Visual regression testing entangles capturing images of the application or website and comparing them using specialized tools that highlight any differences detected. There may be dissimilarities between the two versions. This implies that the appearance or layout of the application has been modified or that an issue or bug needs to be fixed. Visual regression testing is typically utilized in convergence with other forms of testing, such as usability testing or functional testing. This ensures that applications and websites function precisely and meet quality standards. It is convenient when the appearance of an application or website is crucial to its end-user experience or when modifications are frequently made that require close monitoring.

Cloud-based automation has become increasingly widespread due to its scalability, cost-effectiveness, and flexibility. This blog will explore visual regression testing in cloud-based automation. 

Let’s go.

What is Visual Regression Testing?

Visual regression testing is a technique of validating that modifications made to an application or website do not negatively impact the visual appearance of the application’s UI (user interface). It is also known as visual testing or visual snapshot tests. The primary goal of visual regression testing is to guarantee that the end-user experience is visually flawless. This is achieved by verifying that the visual elements and layout of the application or website align with end-users expectations. 

Visual regression testing guarantees code modifications’ impact on end-user experience by resembling pre-execution and post-execution screenshots. It also guarantees visual integrity after updates. Also, visual testing verifies the suitability of the visual aspect of the end-user interface of an application. It is also referred to as visual testing or visual validation. This quality assurance action seeks to verify that the front end of the app displays accurate content and data.

Overall, visual testing ensures that any modifications in the software do not cause style issues. Visual regression testing tools capture screenshots of the current user interface and perform a comparison with the original screenshots to detect any visual discrepancies. The web page should yield identical expectations despite numerous changes. Also, it should look and function in the exact way across a wide array of browsers.

How Visual Regression Testing Works?

To conduct visual testing, it is necessary to employ a test runner for authoring and executing test cases. Also, a browser automation framework is required to emulate end-user measures. It is paramount to have these components to guarantee effective and efficient visual testing procedures. There are tons of programs that can imitate end-user functions. After that, the visual testing program will seize screenshots throughout the procedure. All these screenshots are compared to the initial screenshots captured as a baseline before starting the test.

If, at any moment, any change is detected, then a screenshot is captured. Some of the visual regression testing tools even highlight the discrepancies that were detected from the baseline. After that, analysts determine whether the issue is because of the bugs in the code or some other reason. Then, that issue is fixed by the developers. The issue in the code can also be due to ad integration, which must be handled.

Impact of Visual Errors on the End-User Experience

When you talk about visual mistakes, you are not talking about logical issues in the system; you are talking about aesthetic flaws that cause interfaces to emerge improperly, degrading the end-user experience. 

A few of the UI defects are:

  • Issues with alignment 
  • Issues with rendering 
  • Issues with the font
  • Issues with layout 
  • Issues with responsive layout 
  • Elements that overlap 

Visual errors refer to design or layout issues within online or mobile applications’ interfaces. Such errors can result in users experiencing difficulties when interacting with your app or website. Additionally, these visual flaws can significantly impact the overall user experience of the application.

Understanding the Benefits of Cloud-Based Automation

When it comes to software testing, cloud-based automation can deliver several benefits for organizations. 

  • Firstly, it authorizes teams to run tests at any time and from anywhere, as long as they have an internet connection. This implies that testing can be accomplished across different time zones, saving time and increasing productivity. 
  • Secondly, cloud-based automation diminishes the requirement for physical hardware, which can be expensive and time-consuming to maintain. This can result in cost savings and boosted efficiency. 
  • Thirdly, it authorizes teams to effortlessly scale their testing endeavors up or down, relying on the demands of the project. 
  • Finally, it can help diminish the risk of human error, as automated tests are repeatable and invariant.

How Do Visual Regression Tests Function?

At the core, visual testing functions by capturing screenshots of the user interface before making modifications and resembling it with the screenshot taken after. Then, discrepancies are highlighted for the developer to review. Nonetheless, there are numerous different visual regression testing methods available.

Here are the steps to implement visual regression testing: 

  • Develop the test scenarios and specify what and when to capture in the screenshots.
  • Utilize a visual testing tool to compare the screenshots taken after making changes in the code with the earlier screenshots of the application. 
  • Check for UI differences or issues to report the modifications in the latest product design.
  • If there are any visual bugs, fix them first and then update the screenshots as the baseline images with the new pictures to utilize for future visual regression tests.

Types of Visual Regression Testing 

Visual regression testing is a vital step in guaranteeing that your application looks identical across all devices and platforms. There are several types of visual regression testing techniques, each with its own benefits and limitations. 

Below are different types of visual regression testing:

Manual Visual Testing: Testers and developers perform manual visual testing without the assistance of automation tools. They scan every page, looking for flaws and defects. This authorizes exploratory testing of the UI, mainly at the beginning stages of development. Nonetheless, it is slow, clunky, and prone to human error. 

Pixel-by-Pixel Comparison: Bugs and errors are detected by comparing pixel variations in screenshots, which facilitates accurate identification and resolution of issues. It flags all potential issues due to discrepancies in pixels. Nevertheless, it has the demerit of flagging problems that are invisible to the human eye. Also, it does not influence the functionality of the site. The developer must sort out the potential issues and determine which must be fixed.

Visual AI Testing: It refers to the use of a specialized computer program that is trained to detect visual defects the way a human would but without the potential for human error. The visual AI testing software can be trained to identify dynamic content and flag any issues that arise from unexpected changes.

DOM-Based Comparison: A comparative analysis employing the Document Object Model (DOM) examines the DOM before and following a state shift to identify any variations. This is excellent for discovering when modifications in the user interface are due to embedded or dynamic content. It is also useful when the code changes, but the UI does not. Nevertheless, it tends to generate false negatives/positives and catches some visual bugs.

Overview of Visual Regression Tools

Visual regression testing is a crucial aspect of software testing that entangles comparing the visual output of an application before and after changes have been made. As visual design and layout are integral components of modern applications, it is paramount to ensure that any modifications made do not adversely impact the application’s visual appearance. Visual regression testing can be a clunky task. Nonetheless, with the advent of cloud-based automation tools, it has become more leisurely to execute these tests at scale. 

There are several visual regression testing tools in the market. Each has its own set of features and abilities. Some popular tools incorporate BackstopJS and Wraith. BackstopJS is an open-source visual regression testing tool that authorizes end-users to create custom-made scenarios and test suites. Wraith is an open-source software that effectively captures screenshots of web pages and conducts comparative analysis to detect visual discrepancies. With the help of these visual regression testing tools, teams can guarantee that their web applications look and behave as intended across different browsers, devices, and platforms. 

You can leverage the true capability of visual regression testing tools by using a cloud-based platform like LambdaTest. LambdaTest is a platform driven by AI for orchestrating and executing tests, specifically offering cloud-based AI-supported visual UI testing. It permits the execution of automated and manual tests across more than 3,000+ browsers, real devices, and OS combinations.

Through LambdaTest, you can ensure the proper functionality of applications across a wide range of real-world scenarios. LambdaTest stands out in delivering effortless one-click visual regression testing, which is instrumental in identifying UI regression bugs. The platform’s intelligent testing functionalities enable advanced image-to-image comparisons, rapidly identifying inconsistencies encompassing aspects such as text, layout, color, size, padding, element positioning, and more. Furthermore, LambdaTest supports all major testing frameworks such as Selenium, Playwright, Jest, and many more. 

Of particular significance is LambdaTest’s implementation of parallel testing, which notably reduces the time required for test execution. Notably, the platform seamlessly integrates into your complete CI/CD technology stack, an exciting feature of its offering.


Visual regression testing can provide noteworthy benefits to software development teams by enhancing the speed, accuracy, and reliability of the testing process. It makes life infinitely leisurely for developers on any project. It authorizes them to make sweeping code modifications with the certainty that there is a method in place that will catch any resultant bugs. Incorporating visual regression testing in your software development procedure can help you attain this goal and deliver superior software products to your customers.

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