What is Visual testing?

what is visual testing

What is Visual testing?

In this article, we will learn about a type of software testing known as Visual Testing. We will investigate the various subjects surrounding this testing approach and how we at Q-Pros adopt its various methods to guarantee excellent results.

What is Visual testing?

“Visual Testing” is observing an application’s visible output while monitoring for visual bugs and assessing the output in comparison to what is expected by demand.

Examining an application’s interface is done during the production period by developers, and later end-to-end users (a person who intend to use a product) will seal the deal with the product in the final stages.

The front-end developer’s main concern is to make sure that an application looks good on all browsers and devices with no obvious defects in terms of appearance. HTML and CSS as well as JS are interchangeable and can behave differently from one platform to another. This causes the risk of errors that not only affect appearance but also the functionality.

Considering such concerns, Visual testing is highly demanded by clients as a major step in QA (Quality Assurance).

The distinct value of Visual Testing

Testing your application’s script and making sure each input delivers an expected output on a basic level is not enough. Changes regarding layout and interface could occur due to a lack of compatibility.

Certain elements such as height, width, background color, font style, font size, and position within screen coordinates could change from one platform to another. This change is a result of different operating systems using various rendering methods.

Developers need to have their code written in a way that includes all previous versions of script input. Tools such as Babel could ease up the process by re-writing a code to make sure it could be rendered by all browsers in the same way. Cross-browser testing is a different approach with similar objectives. It includes other aspects than visual ones and focuses on how an application behaves in various browsers, making sure an application is operating based on business requirements and has achieved the desired quality level on all available browsers.

Manual Visual Testing Vs Automatic Visual Testing

Manual Visual Testing

Manual Visual Testing involves testing an application by sheer observation through usage and excavating any notes or anomalies that might stick out. This form of testing is becoming less popular because it is time-consuming.

To put it in perspective, testing an application “manually” will require testing it on all available browsers, in all operating systems, and taking into consideration, available devices and different screen configurations and screen displays. This will take a lot of time to accomplish, and it will open room for false readings.

Automated Visual Testing

In Automated Visual Testing, developers use tools and software to automate the test process and compare visual elements across different screen combinations.

Automated tools such as Selenium or Appium ease the process by running the script and creating UI variations.

As good as it may seem to have all screen combinations generated automatically, it still leaves the burden of testing it yourself to check for any bugs or defects.

One way to make things even easier is to rely on a method called Snapshot Testing.

In short, Snapshot testing creates a bitmap of multiple screen combinations and compares pixels, reporting/highlighting any unexpected changes in color hex code.

By comparing each pair of pixels in combination A & combination B, a snapshot test highlighted the difference as shown in the third table.

The Issue with Automated Visual Testing and The Snapshot Method:

As good as it may seem, Automated Visual testing is not perfect. While companies are relying on automated means of visual testing, the need for manual observation is essential.

Rendering will always cause deference – Relying on an algorithm to detect differences is almost redundant, as the algorithm will always report bugs. This is because pixels do not represent visual elements. Certain rendering activities include algorithms that create pixel differences to run a script.

Encountering some differences on a UI level does not always translate to bugs – some operating systems/browsers adjust CSS codes in a way that is seen as suitable. For Example, Minor changes may occur to the text based on the browser being used.

Benefits of Visual Testing

Visual Testing offers a multitude of advantages:

  • Improved User Experience:By identifying visual inconsistencies and UI defects, Visual Testing ensures a polished and user-friendly experience for everyone.
  • Early Defect Detection:Visual bugs can be caught early in the development cycle, leading to faster and more cost-effective fixes.
  • Reduced Maintenance Costs:Consistent visual appearance across platforms minimizes the need for rework and maintenance efforts later in the development process.
  • Faster Release Cycles:Automated Visual Testing can be integrated into CI/CD pipelines, enabling faster release cycles with the confidence of a visually sound product.
  • Peace of Mind:Visual Testing provides developers and stakeholders with the assurance that the software’s visual presentation aligns with design expectations.

The Future of Visual Testing

Visual Testing is poised for further evolution:

  • Machine Learning Integration:Machine learning algorithms can be employed to analyze visual data and automatically identify potential UI issues.
  • Self-Healing UIs:Imagine UIs that can self-adjust for optimal display across different devices. Visual Testing combined with AI could pave the way for such advancements.
  • Focus on Accessibility:Visual Testing will likely play a bigger role in ensuring UIs are accessible to users with visual impairments.


Visual testing is a field that co-exists with a lot of other non-functional testing methods; it is an inseparable need of QA. At Q-Pros We run scripts on various scenarios to make sure the script runs well on all available platform combinations. We rely on automated tools as well as manually checking visual elements via a team of QA experts.

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