Visual testing is a software testing technique that focuses on visually examining the appearance and functionality of applications and websites. It is essential in ensuring that software meets user expectations and requirements, particularly those with user interfaces.

Visual testing can be performed manually or automated. Manual visual testing involves a tester manually inspecting the software for visual issues. This method is effective in detecting subtle visual discrepancies that can affect the user experience. However, it can be time-consuming and tedious, especially for larger applications and websites.

Automated visual testing uses software tools to detect and report visual discrepancies. This method is faster than manual testing, more efficient, and more accurate. It is especially useful for testing complex web applications with various user interfaces.

In this article, we will discuss visual testing in detail, including its importance, how it works, its benefits, and challenges.

Importance of visual testing

Visual testing is essential because it ensures that software meets user requirements and expectations. Software with a poor user interface can be frustrating and challenging to use, leading to decreased user engagement and loss of revenue. Visual testing helps identify and resolve issues that may affect the user experience.

Visual testing also ensures that software complies with design standards and guidelines. When designing applications and websites, developers follow specific design standards to ensure consistency across different platforms and devices. Visual testing ensures that software adheres to these design standards and guidelines.

Visual testing helps identify issues early in the software development life cycle. Detecting and resolving issues early saves time and money in the long run. Issues identified later in the software development cycle can be costly and time-consuming to fix.

How visual testing works

Visual testing involves visually examining the appearance and functionality of software. This process involves three critical steps:

1. Capture baseline images: The first step involves capturing a set of baseline images that will be used for comparison during subsequent tests. These images serve as the expected result for the software being tested.
2. Test the software: The next step involves testing the software. During testing, new images are captured, and these are compared to the baseline images. Any differences between the two sets of images are reported as defects.
3. Review and validate defects: The final step involves reviewing and validating defects. The defects identified during testing are reviewed and validated to determine their severity and prioritize them for resolution.

Visual testing can be done using either manual or automated techniques. Manual visual testing involves a tester manually inspecting the software for visual issues. The tester compares screenshots of the software to the expected results and reports any discrepancies. Automated visual testing involves using software tools that use machine vision to compare images and report discrepancies.

Tools for visual testing

1. Selenium is a popular open-source framework for testing web applications. It includes a visual testing component called Selenium WebDriver, which can be used to capture and compare screenshots of web pages.
2. Applitools is a cloud-based visual testing platform that uses artificial intelligence to detect and highlight visual differences between baseline and current images. It offers integrations with popular test automation frameworks, including Selenium and Cypress.
3. TestComplete is a functional testing tool that includes a visual testing component called Visual Check. It can capture screenshots of web and desktop applications and compare them to baseline images.
4. Cypress is a modern test automation framework for web applications. It includes a visual testing component called Cypress Image Snapshot, which can capture and compare screenshots of web pages.
5. Percy provides a visual testing platform that can be integrated with a range of test automation frameworks and CI/CD pipelines. It captures screenshots of web pages and compares them against a baseline to detect visual changes. Percy also offers advanced features such as smart visual diffing, pixel-to-pixel comparison, and support for dynamic content. It can be used for testing web applications, mobile apps, and even design files.

Benefits of visual testing

Visual testing offers several benefits, including:

1. Improved user experience: Visual testing helps ensure that software appears and functions correctly, leading to an improved user experience.
2. Faster testing: Visual testing can be faster than manual testing, particularly when it is automated.
3. Increased test coverage: Visual testing can cover a broader range of issues than manual testing alone, as it can detect issues that might be missed by a human tester.
4. Reduced costs: By detecting issues early in the development process, visual testing can help to reduce costs associated with fixing issues later on.
5. Improved quality: Visual testing helps ensure that software meets design standards and guidelines, improving software quality.

Challenges of visual testing

Visual testing can be challenging, particularly when using automated techniques. Some of the challenges of visual testing include:

1. False positives: Automated visual testing can sometimes report false positives, which are defects that are not actual defects. These false positives can be time-consuming to review and can lead to a loss of confidence in the testing process.
2. Dynamic content: Visual testing can be challenging for software with dynamic content, such as web applications that change frequently. In such cases, the baseline images may not match.
3. Browser compatibility: Different browsers can render web pages differently, making it challenging to create accurate baseline images for testing.
4. Localization: Visual testing can be challenging for applications that are localized in different languages. This is because the text and layout of the software can change depending on the language, making it difficult to create accurate baseline images.
5. Maintenance: Creating and maintaining accurate baseline images can be time-consuming and resource-intensive, particularly for larger applications and websites.

Conclusion

Visual testing is an essential testing technique for ensuring that software meets user requirements and expectations. It involves visually examining the appearance and functionality of software and can be performed manually or automated. Visual testing offers several benefits, including improved user experience, faster testing, increased test coverage, reduced costs, and improved quality. However, it can also be challenging, particularly when using automated techniques. To overcome these challenges, testers must carefully plan and execute their visual testing efforts.