Visual testing is a type of automated software testing that checks an application's user interface (UI). Unlike functional testing, which checks software's behavior and functionality, visual testing tests software from a purely visual standpoint.

Visual testing — sometimes referred to as visual regression testing or UI testing — checks the components or pages of an application's UI across browsers and responsive widths. By utilizing image rendering and processing, visual testing works by comparing new UI images against previously generated UI images for visual changes.

Including visual testing in the development stage of an application's lifecycle allows teams to detect visual regressions or bugs before they make their way to production, ensuring that the UI always appears correctly to end-users. In this Refcard, we'll review how visual testing fits into the software testing ecosystem, its use cases and best practices, and how to get started with a hands-on visual testing tutorial.

Developers have been debugging software as long as they've been building software. The concept, practice, and culture of software testing, however, have all dramatically evolved in recent years.

The Rise of Test Automation

Beyond solely proving that software works and providing mechanisms for detecting faults, software testing today aims at preventing faults — or bugs — in the first place. In the last thirty years, that task has become more difficult.

Software has become more accessible across a variety of devices and gets distributed across a plethora of channels and environments. The complexity of software has also dramatically increased with technological improvements, mounting consumer expectations, and intensified market competition.

To help organizations meet those pressures, methodologies like Agile and DevOps have gained popularity, promoting faster and more reliable deployments. Faster deployments, however, increase the risk of releasing bug-ridden software.

To help mitigate that risk, test automation as we know it has become a mainstream best practice amongst developers and product teams. Test automation tools and testing methodologies have gained popularity to help teams test their software more efficiently and to further entrench test culture into development processes and organizations.

This is a preview of the Visual Testing Refcard. To read the entire Refcard, please download the PDF from the link above.