New to visual testing? Discover the essentials in our comprehensive guide. Learn what is visual testing, why it matters, and how to begin.
OVERVIEW
Visual testing ensures the accuracy of a software application with respect to its intended appearance and behavior. It helps identify any unintended changes in visual presentation or functionality. This process involves comparing an initial version of the application or website (referred to as the baseline) with the most recent iteration to detect any visual discrepancies that may have occurred.
Today’s software industry is experiencing massive competition in releasing new software with immense features and interfaces. To excel in the competition, new releases of software applications are deployed constantly, which indicates that there are regular updates done by changing the existing line of code. However, even a slight change in the code can impact the performance and function of the existing code, which may affect user experience.
In this fast-paced digital world, user experiences are critical, and ensuring a visually perfect UI of software applications is required. Also, attractive designs and layouts with different colors, typefaces, and other visual components are significant for user engagement.
As per one of the reports, 88% of users are less likely to return to a website after a bad experience. Also, a Stanford study says that 94% of people agree that web design impacts the website's first impression. Sometimes, we may stop using certain websites or eCommerce applications if their user interface is not up to par. This could even lead to organizations losing business deals.
To ensure that the user interface is both visually appealing and user-friendly, we need to conduct an extra layer of testing known as visual testing. This type of testing verifies the visual elements' appearance and layout, ensuring they meet design standards and provide a seamless user experience. So, let us understand visual testing in detail.
Visual testing, also called visual UI testing, is a testing approach to verify the user interface, visual appearances, graphical user interface, and behavior of the software applications. Simply, a visual test helps to check the look of the software applications and detect any visible bugs in the appearing pages of mobile apps or websites. Following this, a comparison is carried out between the visible output of software applications and the expected design results.
What exactly is addressed in visual testing? Is it just the appearance of the software applications? Visual testing examines every element on webpages to ensure correct shapes, sizes, and positions across all browsers, devices, and operating systems. Additionally, visual tests verify the various behaviors of webpages, encompassing elements such as labels, buttons, navigation, content, and other functionalities.
This helps the software developers to have a unified experience for their users. They can quickly identify any discrepancies or errors in the visuals of the web applications or websites by analyzing expected and rendered output. Also, with this, they can ensure that their software applications meet usability standards and are optimized for different platforms.
With visual testing, developers and testers ensure that the developed software applications give a uniform user experience to all end users irrespective of device or browsers and their versions.
However, many software professionals agree that functional tests are sufficient to identify any visual bugs. But this is not a reality. Let us learn about this in detail from the below section.
You must understand that functional testing in software applications can help validate how efficiently its UI works. For example, while working with an eCommerce application, when a user clicks "Pay Now," the functional test ensures that the link correctly deducts charges from the user's account. However, verifying specific details, such as the alignment of the "Pay Now" button through functional tests requires significant effort.
Functional tests may overlook the following aspects:
Attempting to validate these aspects using functional tests can result in chaining lengthy assertions together to capture visual differences across releases. Consequently, the scripts become unreliable, break, and are challenging to maintain over subsequent releases.
However, these challenges can be addressed by implementing automated visual testing. Visual tests primarily focus on validating the visual elements of an application, offering a comprehensive assessment of its appearance, arrangement, and design, guaranteeing a seamless user experience in terms of visuals.
Thus, it is essential to note that a functional test alone is not enough to guarantee any absence of visual bugs. Visual testing must be included in the Software Testing Life Cycle to assess your software applications visually.
Note : Run automated visual tests in a click with SmartUI CLI. Try LambdaTest Now!
Visual testing primarily focuses on the appearance and behavior of the user interface, whereas functional testing centers on assessing the functionality of the software application. Functional testing does not capture visual defects such as alignment, pixel-to-pixel comparison, rendering, layout, overlap, font changes, and responsive layout issues.
Most software tests are designed to verify that various aspects of the software function as intended. However, these tests often neglect the crucial visual aspects from the users' perspective.
For instance, in the example provided at the beginning of this tutorial, functional tests would have indicated a flawless working website, including the Checkout button. Nevertheless, users faced a significant issue and could not execute one of the website's primary functions.
Visual Testing | Functional Testing |
---|---|
It focuses on the appearance and behavior of the user interface. | It focuses on testing the functionality of the software application. |
It aims to verify the correct and consistent display of visual elements across devices, OS, and browsers. | It aims to verify that features and functionalities work as intended. |
Visual testing is performed due to frequent visual errors that are often underestimated. It allows you to spot defects not identified by other UI tests easily. Some crucial rationales for visual tests include:
Visual testing has several advantages in the Software Testing Life Cycle. Let us learn those from the below points:
Visual tests are not an exception to other software testing types as they hold some disadvantages, too. Here are some of those:
Let us understand the significance of visual testing with an example explained below.
Consider a complex software application developed for financial analysis, which includes various data visualization components and interactive charts. Here, ensuring that every visual function runs smoothly is crucial.
The testers mainly perform automated tests to validate the main functionalities of the software application, like calculation and database interactions.
However, the application must render the same functionality when it goes live and is deployed in the production environment. When the application was further validated by running a test, the user encountered visual defects like charts and graphs that could not render appropriately on particular screen resolutions and browsers. It was found that some of the labels and axes of the charts are misaligned thus interpreting data as a challenging task.
Such visual bugs were unidentified by the functional test, and to address those, visual tests were performed. This verifies the correct appearance of each data visualization component and ensures that charts and graphs are correctly displayed across all platforms. Thus, visual UI testing ensures an overall user experience.
Visual testing is divided into two different types based on the functionality that ensures that each element of the pages are tested and verified for a uniform user experience. Those types are static and dynamic.
In static visual testing, the web page's image is captured, or its screenshot is taken to compare it with its main baseline image. It helps to identify any discrepancies in the elements like text, size, fonts, and others in a webpage. But why is the screenshot taken? Because it provides an easy approach for comparative analysis and is done to check that the page looks similar on various devices and browsers.
Static testing is effective in checking the layout and styling of the page and ensuring that all the webpage features are working as intended. This uses techniques like bitmap comparison that takes snaps of the web page image and then compares it with the baseline image example.
The dynamic visual test allows testers to observe how users interact with or use the software application. For example, this test considers the use of web page elements like buttons or menus by simulating user actions.
You can quickly identify the common UI issues, which might be missed or overlooked by the static test, like inaccurate size images. With dynamic visual tests, you can also record the user actions by leveraging dynamic tools. This can be replayed on browsers, versions, and devices to find visual bugs.
There are three distinct categories of visual testing, categorized by the type of evaluation required. These categories include:
This form of testing entails a manual review of the software's visual components to ensure their proper functionality and adherence to the desired appearance. For instance, scrutinizing the screen to identify user experience or visual presentation issues.
However, this process can prove to be demanding for several reasons, including.
This method employs automated testing frameworks to compare the visual elements of the software application with a predefined set of anticipated results. The tool can validate the visual aspects based on the test cases.
However, automated visual UI testing also presents its own set of challenges, such as
Different testing approaches, like regression testing, will help you ensure that software upgrades do not introduce unforeseen issues in its visual attributes. An example of regression testing is contrasting the appearance of a web page before and after an update to ensure that the overall appearance remains consistent.
Numerous specialized testing subtypes are tailored to project requirements within these three primary categories. Let us now understand those types of different tests.
Automated visual tests entail examining the visual aspects of applications under test and comparing the results against baseline screenshots to validate their alignment. This approach also assesses attributes related to visual aesthetics, including consistent rendering, precise alignment, and correct dimensions.
It's worth noting that this method may not be suitable when time constraints are a concern. Visual regression testing demands a significant time commitment and should be reserved for scenarios with strict deadlines. It is not ideally suited for purely automated or manual execution. Instead, a combination of automated and manual visual regression testing typically yields optimal results. It is prudent not to rely solely on error rates generated by tools when conducting image comparisons.
Visual regression testing is one of the most reliable methods to achieve the desired outcomes. It is carried out in conjunction with functional testing to evaluate an application's visual integrity. This can be a complex aspect to address, as functional automation frameworks are primarily designed to handle functional aspects.
We have now understood that visual tests address the visual aspects of software applications. Here are some methods by using which can execute visual tests.
However, it's important to note that this process is time-consuming and may not be practical for larger datasets. This approach can identify compression artifacts or check color accuracy in complex imagery.
Note : Perform AI-powered visual UI testing on the cloud. Try LambdaTest Now!
To automate visual testing, there is always a need for different automated testing tools that help identify issues and ensure their fixes. As previously mentioned, automating the visual test is not just limited to saving time and testing efforts.
When you perform the visual test, you need a test runner for writing and running the test. This requires developers and QA to write code that can quickly reproduce user actions. Here, each test has assertions that define conditions that will either pass or fail.
To address this, you must organize tests into different blocks and put them in separate files, which will be used to test a specific module or software function. When you are done with writing the test, here you will need visual test tools to interact with the browsers. They will not only support visual tests but also help generate screenshots of web pages. Let us know about these tools:
With LambdaTest, performing intelligent image-to-image comparisons becomes effortless, allowing you to identify visual discrepancies in various elements, including text, layout, color, size, padding, and element positioning.
What sets LambdaTest apart is its ability to facilitate automated visual tests using different testing frameworks like Selenium, Cypress, Playwright, Storybook, Appium across multiple programming languages, including Java, Node.js, and C#.
Moreover, LambdaTest's parallel testing capabilities significantly reduce test execution time, and its seamless integration with various CI/CD tools makes it a standout choice for achieving flawless software applications with impeccable visual characteristics.
For more information on automated visual regression testing on LambdaTest, please check out the below tutorial:
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With Selenium, you can interact with web elements and navigate through web pages using the WebDriver API. An interesting aspect of Selenium is its compatibility with various web browsers, making it versatile for conducting visual tests across different platforms.
Its unique ability to wait for elements to appear and become interactive enhances the reliability of visual tests. It also offers control over network requests and XMLHttpRequests (XHR), allowing you to simulate and intercept responses. Additionally, you can extend your Cypress visual regression testing using plugins like "cypress-image-snapshot”.
Performing visual UI testing comprises different steps and phases that require careful consideration. Let us learn about those in detail:
When you have all the above in place, the next stage comes the steps for implementation.
Step 1: Identify UI elements and choose a testing approach
Begin by identifying the UI elements that require testing. You have the option of manual or automated testing. Manual testing involves inspecting each UI page, whereas automated testing employs algorithms to compare visual components against a baseline.
Step 2: Balance automated and manual testing
Consider whether your software application demands detailed manual testing to validate attributes like fonts, colors, and animations. While automated tests are generally faster and more precise, a blend of both approaches might be necessary. Regardless of the chosen method, the goal is to ensure consistent UI functionality across devices and users.
Step 3: Ensure cross-platform compatibility
After pinpointing the elements for testing, ensure their accurate representation and support across various browsers and devices. This comprehensive cross-platform testing can be facilitated using tools like pixel-to-pixel comparison utilities or screenshot comparison software, simplifying the task of comparing versions against the baseline.
Step 4: Leverage automated visual testing tools
Automated visual test tools play a crucial role in identifying deviations from the design and generating detailed reports on these disparities. The objective is to validate the precise presentation and operational effectiveness of all design elements, regardless of the browser or device being used.
Step 5: Integrate automated testing into development workflow
Integrate automated testing seamlessly into your development workflow. Doing so not only saves time and resources by detecting issues before they impact production or launch and ensures consistent rendering of the software's user interface (UI) for all users. Identifying issues before they reach production is invaluable.
Step 6: Implement UI change monitoring
Establish a monitoring system to swiftly and accurately detect UI changes. This proactive approach promptly resolves inconsistencies, ensuring your software's UI's ongoing quality and consistency.
Cloud-based visual regression testing is viable for web and mobile app testing without maintaining the in-house test infrastructure. Testing your software applications for visual bugs on the cloud helps you leverage different browsers, devices, and operating systems and reduce coverage limitations.
With an AI-powered SmartUI platform like LambdaTest, you can perform manual and automated visual regression testing across 3000+ desktop and mobile environments. Let’s see how to perform visual regression testing on LambdaTest.
Manual Visual Regression Testing
You can also use different view options like Side by Side Mode and Slider Mode.
Automated Visual Regression Testing
To perform automated visual UI testing ( or SmartUI testing) on LambdaTest, please follow the below steps:
To run visual tests using LambdaTest, check out the documentation: Smart UI - Visual Regression Testing on Cloud.
Here are a few best practices of visual regression testing:
Visual testing is a software testing method that validates the visual design and layout of a user interface or graphical component in a software application. Its significance in web development cannot be overstated, as it ensures a visually appealing appearance and optimal functionality.
This comprehensive guide covers various aspects of visual tests, including categories, advantages, and accessible tools. This guide gives you a solid understanding of the fundamentals and a clear starting point. With practice, you will quickly become a proficient visual tester.
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Nazneen Ahmad
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