The Ultimate Automated Visual Testing Tutorial For 2023
In the era of digital technology, people are able to access their favorite websites and applicationns on different devices.
Businessess should make sure to optimize their websites UI and UX for picture-perfect releases.
In this article, we will learn about automated visual testing and how it helps us in delivering better user interface (UI) and user experience (UX) to the end user.
Usually defects made it to production are often UI defects.
Most of the organizations use functional testing tools like Selenium and Appium to test their applications. These tools are not designed to find rendering issues (visual bugs).
To find the visual bugs we need to perform visual testing.
What is a Visual Testing?
Visual Testing is also known as Visual Checking or Visual Regression Testing or Visual UI Testing.
Visual testing in software development is a process of reviewing and detecting UI changes in an application.
Visual regression testing ensures that a graphical user interface (GUI) of a web or mobile application is properly displayed and visible to end users in different browsers and at different screen widths as it was originally intended.
Visual testing is done to review the visible output of an application, comparing it to the corresponding expected result.
Once the developer creates an appliction, QAs make sure that the application has no visual bugs by verifying it on multiple browsers, operating systems, devices, and screen resolutions.
What are Visual Bugs?
Visual bugs are problems with the design or layout of an interface within a web or mobile application. When they pop up, users may encounter glitches in the application. These visual bugs ruin the user experience of an application.
Some of the common UI defects are as follows:
- Font issues (unknown marks instead of text)
- Alignment issues
- Layout issues
- Rendering issues
- Overlapping elements
- Responsive layout issues
Most of the users won’t return to your website or app, if they face negative experiences when they are accessing your website or app.
A successful organization needs to constantly monitor these types of issues to ensure that their clients still have the best user experience possible. Otherwise they will be at risk of not driving higher levels of customer satisfaction and negatively impacting revenue, service subscriptions and performance in general.
If a visual bug is restricting user to access the key functionalities of an application then we should report it as a functional bug.
Must Read: Functional Testing vs Non-functional Testing
Why is Visual Testing Important?
Assume you are accessing an ecommerce website on your desktop and added some items to your cart.
After sometime you have opened the same ecommerce website on your mobile to add some more items.
But you are unable to add items due to an issue where product image is overlapping the ‘Add to cart’ button.
Obviously this will ruin your experience with that ecommerce site and you will move on with another site.
Visual testing plays a vital role in fixing the visual bugs and gives better user experience.
To do visual testing we need to test the application in multiple browsers, operating systems, screen sizes etc.,
Keep in mind that mistakes in the user interface can result in lost sales.
Why Can’t We Find Visual Bugs With Functional Testing?
With functional tests we can make sure the application logic is working as intended but we cannot find visual bugs at the GUI level.
Functional tesitng measures functional behavior but cannot detect changes caused by rendring subleties or CSS changes. Where as visual tests can find changes caused by rendering subleties or CSS changes.
Functional tesitng: It ensures that the software is working as intended.
Visual Testing: It ensures that the software is looking as intended.
Implementing visual testing early in the development cycle along with the functional testing allows us to find and fix visual bugs before releasing the application to end users.
Software teams usually spend a lot of time and work hard to develop websites that meet end-user requirements.
Despite these efforts being wasted if the website doesn’t provide a consistent user experience across platforms, devices and browsers.
To maintain the positive brand value, the website should be uniform across platforms, devices, and browsers.
We can do visual testing either manual way or using automated tools. Let’s see which type of visual testing gives better results.
What is Manual Visual Testing?
Developers or QAs involved in finding visual bugs manually by comparing the design expectations to the visual output on various devices, operating systems, browsers and screen sizes and make a note the differences by taking screenshots.
- It is not easy to find the minor UI changes through manual visual validation testing.
- It is a time consuming process
- It is an expensive task and error prone due to human intervention
- It is impossible to test the application in all the device permutations through manual visual testing.
Visual regression tests are typically written with automated testing frameworks like Selenium WebDriver, but can be run manually by comparing two sets of screenshots taken from the same pages within the application.
Visual regression testing with manual functional tests is used when it’s not feasible or cost effective to create an automated Visual regression test.
Manual visual testing is tedious and time consuming task.
To overcome these issues we opt for automated visual testing tools.
Here comes the automated visual testing.
What is Automated Visual Testing?
Automated visual testing will help us to test our application quickly and its scalable when it comes to coverage, time, and overall quality of your website or mobile application.
Automated visual regression testing allows testers to automate tests that monitor visual aspects of software applications, such as web pages, desktop user interfaces or mobile apps.
Automated visual checking is the process by which automated tests are created to verify whether changes have been made to applications’ user interfaces.
Manual Visual Testing Vs. Automated Visual Testing
|Manual Visual Testing||Automated Visual Testing|
|There is no need to invest in Visual Testing Tools.||Need to invest in Visual Testing Solution.|
|Need to manually compare visual outputs from a variety of devices.||There is no need to manually compare visual outputs from a variety of devices.|
|Slower than automated testing.||Much faster than manual testing.|
|Not able to find more visual bugs compared to automated visual testing.||Able to find more visual bugs compared to manual visual testing.|
Advantages of Automated Visual Testing Tools
Automated visual regression testing tools compare images against each other “pixel by pixel” to look for changes due to bugs or bad practices and allows companies to ensure these changes do not negatively affect the end product experience.
- Allow to replace hundreds of assertions with a single visual snapshot.
- Automated Visual Testing tests UI across browsers, screens, devices.
- Saves time and resources spent manually testing.
- Performs UI tests across multiple platforms, devices, browsers, and operating systems.
How The Visual Testing Process Works?
The visual testing is performed to compare UI screenshots of a software against baseline images to see if any changes have occured.
Step #1: Run the Application Under Test (AUT) and take screenshots.
Step #2: Screenshots are rendered across browsers, operating systems, screen sizes and devices.
Step #3: Compare the screenshots against the baseline images and analyse for visual changes.
Step #4: Report the differences if any visual changes are detected
Step #5: Update the baseline images as per requirement.
Popular Commercial Visual Testing Tools
If you’re interested in purchasing a Visual Testing solution, check out the list of vendors below that offer this service. Here is a detailed guide on Best Visual Testing Tools.
- Applitools – Best for desktop – web application visual testing.
- Percy (BrowserStack) – Best for web application visual testing.
- Kobiton – Best for mobile testing teams.
Visual testing is a method of software quality assurance, which analyzes how the user interacts with your website or app. It checks to see if it meets usability and accessibility standards and looks for bugs in site navigation, graphics, fonts, color schemes, etc.
Automated visual testing tools are great because they allow you to test on multiple platforms at once without having to manually do so yourself.
If this article has peaked your interest in automated visual testing tools, you can check our detailed guide on best visual regression testing tools in the market.
FAQ: Visual Regression Testing
What are the best Code/Script Based Open-source Visual Validation Tools?
Following are the list of code/script based visual testing tools that are free to use and open-source.
#1. FBSnapshotTestCase (Uses XCTest)
#2. Gemini (Uses JS DSL)
#3. Needle (Uses Python)
#4. PhantomCSS (Usess CapserJs)
#5. Pix-Diff (Uses JS and Protractor)
#6. Rspec Page Regression (Uses Capibara)
#7. Selenium Visual Diff (Uses Java and WD)
#8. Specter (Uses JS DSL)
#9. VisualCeption (Uses PHP and CodeCeption)
#10. Vizregress (Uses .NET and WD)
What are the best Configuration Based Open-source Visual UI Testing Tools
Following are the list of configuration based visual validation tools that are free to use and open-source.
#3. CSS Visual Test
#4. Grunt Photobox
#7. Galen Framework
#9. Snap And Compare