In a nutshell: When interacting with your app or website, the first thing your users notice is its visual appearance. This guide covers: What is a visual regression test?, Why are visual regression tests important?, Don’t functional tests catch visual bugs?, Creating your test scenarios.
When interacting with your app or website, the first thing your users notice is its visual appearance. First impressions are not only crucial, but they are often definitive. Today, visually perfect user interfaces are a standard that consumers expect.
Essential for ensuring this quality is the visual non-regression testing helps monitor the integrity of your user interfaces to protect your brand’s image. In this article, we’ll explore what visual regression testing really is, why it has become essential, and how to implement it effectively.
What is a graphical nonregression test?
Non-regression testing (NRT) is a technique used to verify that a new or modified feature works correctly, assuming that the previous feature has not been affected.
The advantage of this type of test is that testers check only what has been changed, rather than the entire product, which saves time and resources. The goal of non-regression testing is to determine whether any undesirable behavior has emerged as a result of the most recent software changes.
Graphical regression testing applies this same logic to the visual aspects of the software.
Testers check whether the most recent code changes have broken any part of the software's visual interface by comparing screenshots taken before and after the code changes.
Even minor changes can have unintended consequences or cause new bugs to appear.
Ultimately, the goal of visual regression testing is to ensure that the user experience is visually flawless by verifying that the layout and visual elements meet expectations.
Why are graphical non-regression tests important?
Graphical non-regression testing is important to prevent costly visual bugs from negatively impacting the end user.
Visual bugs negatively impact users' visual experience when using software, and in many cases, these bugs can directly lead to lost sales and damage to a brand's reputation.
For example, suppose a user opens a website and wants to click a button, but can't because an ad is covering the button.
The user is naturally frustrated and wonders how such an obvious problem could have escaped the web developers' attention, and they will associate this brand with a frustrating user experience.
They might think to themselves, “If they can’t even do these obvious things right, why would I want to buy one of their products or services?”
There are hundreds, if not thousands, of device-browser-operating system combinations
In today's world, there is a seemingly unlimited number of device-browser-operating system combinations that implement "pixel code" conversations in their own way.
Differences in screen sizes and resolutions must also be taken into account.
The same software may appear different (or distorted) on different devices, which underscores the importance of conducting graphical regression testing.
Don't functional tests catch visual bugs?
Functional tests are effective at detecting a variety of bugs, but not visual bugs. In fact, your website or application may pass all your functional tests but still have visual bugs. Furthermore, some tests aren’t strictly necessary , such as checking a page footer or the presence of a breadcrumb trail.
To ensure that these undesirable anomalies do not go unnoticed, it is necessary to perform visual non-regression tests.
How do automated graphical regression tests work?
Visual regression testing works by taking screenshots of the user experience before a change is made and comparing them to screenshots taken after the change usingan automated testing tool.
To do this, developers first write code that replicates user actions and insert commands at the appropriate points in the code to take a screenshot.
The first time the test code is run, an initial set of screenshots is recorded to serve as a baseline against which all subsequent changes will be compared.
After defining the baseline, the QA team runs the test code in the background, and every time a change is detected, a screenshot is taken.
Each screenshot is compared to the reference image corresponding to that particular section of the code and software. If any differences are found between the images, the test is considered a failure.
Once the test code has run completely, a report is generated automatically, and a reviewer then examines all images flagged as having changed from their baseline.
If bugs are causing these differences in the images, the developers can fix them and run the test again to verify that the fixes worked.
If changes to the user interface result in discrepancies, developers will need to review the screenshot and update the reference images against which visual tests can be run in the future.
Can you run the graphical non-regression tests manually?
Developers can take some time after each new change to manually scan the pages and look for visual defects.
However, this method is slow and complicated to implement for an entire application or website, not to mention the risk of human error.
That said, manual testing conducted in this way can facilitate ad hoc or exploratory UX testing, particularly in the early stages of development.
Implementing Automated GUI Regression Testing – Step by Step
Automating visual non-regression testing saves time, reduces the risk of human error, and ensures the software's visual appeal.
For visual regression testing, you will need:
- A testing tool for writing and running tests.
- An automated testing tool for replicating user actions.
1. Create your test scenarios
Define what should be captured in the screenshots and at what point in the test they will be taken.
This is where you ensure that these scenarios include a variety of user interactions that replicate what the software will have to handle in the real world.
2. Use your automated visual testing tool to compare recent screenshots
This step involves comparing recent screenshots (taken after the most recent code changes were implemented in the software) with those taken earlier.
The tool will generate a report detailing all the differences detected between two sets of screenshots.
3. Check the results
One or more testers verify and report whether the changes made have produced the expected results or whether any issues have arisen.
4. Fix any bugs as needed and update the baseline
If you find any bugs, fix them (or report them to the relevant developers so they can be fixed). Once that's done, update the screenshot to serve as a reference for future visual tests.
Mr Suricate Simplified graphical non-regression testing through no-code automation
Checking the visual aspects of your user journeys is crucial to protecting your brand image.
A no-code test automation platform such as Mr Suricate makes these checks easy, so you can ensure visually perfect user journeys in the most efficient way possible.
FAQ
What is a graphical nonregression test?
Non-regression testing (NRT) is a technique used to verify that a new or modified feature works correctly, assuming that the previous feature has not been affected.
Why are graphical non-regression tests important?
Graphical non-regression testing is important to prevent costly visual bugs from negatively impacting the end user. Visual bugs negatively affect users’ visual experience when using software, and in many cases, these bugs can directly lead to lost sales and damage to the brand’s reputation.
Don't functional tests catch visual bugs?
Functional tests are effective at detecting a variety of bugs, but not visual bugs. In fact, your website or application may pass all your functional tests but still have visual bugs. Furthermore, some tests aren’t strictly necessary, such as checking a page footer or the presence of a breadcrumb trail.