Regression testing ensures modifications to the source code do not interfere with the existing system. It also sees that software functionality and codes have regressed. Visual testing evaluates the visible outcome of an app and compares that outcome against the results expected by design. Visual regression testing is a critical process that ensures an application or website adheres to its expected appearance and functionality without any unintended alterations.
Maintaining a consistent visual appearance and user experience over time is critical for any application or website. Visual regression testing is an essential part of WordPress web development that ensures it. The process includes comparing snaps of a website before and after updates to spot any visual dissimilarities that may have arisen. Furthermore, visual regression testing helps spot issues, including broken graphics, textual misalignments, and unexpected design shifts, by zeroing in on the website’s outward appearance.
This blog will explore the concept and benefits of visual regression testing in a web development project.
Let’s begin!
Table of Contents
Introduction To Visual Regression Testing
Visual regression testing is an approach to confirm that the user experience is visually perfect and aligns with the expected outcomes. Visual regression testing solely concentrates on outward appearance, including layout, graphics, design, and typefaces.
As websites increase in complexity and undergo more frequent updates involving multiple contributors, the likelihood of visual regressions also rises. Unintentionally modifying the visual aesthetics of a website often occurs as a common consequence of even seemingly minor alterations to code or content. With visual regression testing, developers can fix this before they affect end-users. A website’s user satisfaction, economic results, and reputation can benefit from a uniform aesthetic style.
Importance of Visual Regression Testing
Visual regression testing is necessary to prevent expensive visual bugs or issues from escaping into production. Neglecting to perform visual validation can significantly impact the user experience and, in numerous instances, reduce sales. Conventional functional testing works by validating data input and output. This testing method catches bugs and issues but cannot discover visual bugs. These bugs or issues can slip through a well-tested application without visual regression testing.
For instance, if there is any visual bug in the website, the page will pass the functional tests as all required elements are present on the page and have loaded without issues. Nevertheless, the existence of visual bugs is obvious. Here, visual regression testing comes into play. It will easily catch the visual bugs and issues before it slips into production.
Visual regression testing can also optimize functional testing practices and improve their efficiency. This is because visual tests can “catch” the elements on a page. They do not rely on individual coded assertions utilizing unique selectors to validate each element. In a conventional functional testing suite, the creation and upkeep of these assertions can be labor-intensive, particularly as the application changes. Visual regression testing significantly simplifies this process.
When visual regression tests are expected at the earlier SDLC phases, spotting visual discrepancies becomes much easier. It also saves significant time and resources, which can be used for other development stuff. In short, along with the flawless application functionality, it is vital to have a phenomenal user interface and experience. Whether we talk about UI or UX, visual regression testing is an absolute part of quality assurance. Areas that can benefit significantly from visual testing include web and mobile applications and customer systems within industries such as banking, travel, airlines, and marketing.
How Do Visual Regression Tests Work?
Visual regression testing operates by capturing UI screenshots before making a change and then comparing them to a screenshot taken after. The differences in both screenshots are highlighted for the developers to review and resolve. There are numerous different visual regression testing techniques available.
Additionally, visual regression testing can assist you in spotting bugs in the following cases:
- Manual code changes
- Plugin and core software updates
- Server issues
- Missing quality assurance
- Malware and other malicious code
- External software and API issues
Types of Visual Regression Testing
In general, there are four types of visual regression testing:
Manual Visual Testing: This type of testing can be done manually, without any tools. Developers and designers take time during every release to review pages, manually examining for visual defects. Manual testing can be time-consuming and labor-intensive when applied to an entire application.
Pixel-by-Pixel Comparison: Pixel-by-pixel visual testing approach compares the before and after taken screenshots and analyzes each at the pixel level. This alerts the developers of any discrepancies discovered. Pixel comparison flags all possible issues and includes irrelevant differences that are invisible to the human eye and do not affect usability. These issues include anti-aliasing, rendering, or padding/margin differences.
DOM-Based Comparison: An evaluation utilizing the Document Object Model (DOM) analyzes the DOM before and following a state alteration, identifying and highlighting any variances observed. This draws attention to any changes made in the code that comprise the DOM but is not truly a visual comparison. It can produce false positives or negatives whenever there is a change in the code or UI. Therefore, the test outcomes can be flaky and require developers’ interference to deliver the correct results.
Visual AI Comparison: This type of visual regression testing uses Visual AI that catches the UI in the same manner a human would. It recognizes the differences humans would notice and eradicates the time-consuming false positives issues.
Implementing Visual Regression Testing in a Web Development Project
Incorporating visual regression testing into the CI/CD pipeline is best. It saves time, diminishes the possibility of human error, and ensures the visual appeal maintenance of the software.
Here are a few factors to consider while implementing virtual regression testing:
Choose the Right Visual Testing Tool
The selection of a suitable tool can significantly streamline the visual regression testing process and improve overall efficiency. When evaluating potential options, there are several factors to consider. Firstly, the tool should provide comprehensive support for capturing and comparing screenshots or images of web pages or applications.
It should have robust image analysis capabilities, detecting even the smallest visual differences. Cloud tools like LambdaTest allow developers to capture screenshots of web pages across different devices and browsers, compare them to baseline images, and detect any visual differences automatically.
LambdaTest functions as an AI-powered test orchestration and execution platform for conducting manual and automated tests on a large scale. It enables users to conduct real-time and automated testing across 3000+ environments and offers a platform for executing real device cloud testing.
The platform facilitates visual testing across a wide array of browsers, guaranteeing consistent appearance and functionality of web applications for end-users, regardless of their browser preference. With LambdaTest, you can efficiently verify the responsiveness of your web applications by testing them on various devices and screen resolutions. This ensures your application delivers an optimal user experience across diverse devices, from desktops to smartphones.
Ensure Consistency Across Browsers
To maintain uniformity across browsers within a web development project, it is essential to conduct comprehensive testing and validation of visual elements across various platforms. Browsers may render web content differently, which gives rise to differences in how the website or application is displayed to the users.
Cross-browser testing allows developers to discover and address all design, layout, or functionality issues. This implies testing the website or application on various browsers, namely Chrome, Firefox, Safari, and Edge, on different versions and operating systems.
Set up a Baseline Image
The baseline image serves as the reference point for future tests and helps to identify any visual changes in subsequent iterations. To create a baseline image, developers should capture a screenshot of the website or application in its desired state. This image should represent the expected visual appearance and layout. It is necessary to ensure that the baseline image is created on all target browsers and devices to reflect the intended design accurately across different platforms.
Identify Visual Elements to Test
To effectively implement visual regression testing in a web development project, it is essential to identify the specific visual elements that need to be tested. This includes a detailed review of the website or application’s design and functionality. Key visual elements to consider can be the overall design, menus, buttons, forms, images, and dynamic and interactive components. It is critical to prioritize the elements that are critical to the user experience and can be affected by code changes or updates.
Run Automated Visual Tests
Automation tools aid developers in efficiently and accurately detecting any misalignment or display errors in the product development lifecycle. Through these tests, web application’s appearance and functionality can be easily examined over various devices and browsers, which helps spot visual bugs quickly before they get to the production environment. Automated visual tests save time and effort and enhance the overall quality assurance process by providing precise and consistent results.
Analyze and Compare Results
Once the automated visual tests have been executed, the next crucial step in implementing visual regression testing is to analyze and compare the results. This process implies a detailed review of the screenshots or videos of the web application taken with different devices and browsers. Thereby, the developers can compare the differences and inconsistencies between the expected output and the actual output of the development process.
Analyzing the display carefully from different perspectives is necessary, which may involve layout, font rendering, image display, and color accuracy. This thorough analysis enables developers to pinpoint specific areas that require attention and further investigation.
Create a Test Plan
The test plan acts as the roadmap for the testing process that covers objectives, the scope, and the approach for the visual regression tests. Start by describing the goals of the testing, like achieving visual congruency across multiple devices and browsers. Next, identify the specific test scenarios and test cases that need to be executed, including the different visual elements and interactions that will be covered.
Also, establish the testing environment, including the tools and technologies to capture and compare screenshots. The test plan should also outline the roles and responsibilities of the testing team, as well as the timeline and milestones for completing the visual regression testing.
Continuously Monitor for Regressions
Regression occurs when previously functioning features or elements of a website experience issues after implementing new changes or updates. Through constant monitoring for regression errors, developers can detect any visual abnormalities resulting from any changes made to the code.
This is accomplished with the help of automatic visual regression testing tools that compare screenshots of the website before and after the updates to discover any changes. Performing these tests regularly allows the developers to detect and fix the regressions early on, thus the website functionality and visual consistency are maintained.
Conclusion
Appropriate implementation of visual regression testing can be a game changer for any organization. When executed regularly, visual regression testing is authorized for preventive maintenance and diminishes the likelihood of any inconsistencies tarnishing your live page post after any kind of code modifications. By utilizing automation and adhering to a well-defined process, developers may effortlessly include visual regression testing in their testing processes.
