Automated visual regression testing with Jest

Developers traditionally write various types of tests, such as unit, integration, and end-to-end tests, to ensure functionality and confidence in their code, but visual testing of the design is often overlooked. This article explores automating visual regression tests, which provide assurance that an application's appearance aligns with design expectations as code changes. While manual visual checks are common, the article suggests setting up automated visual tests using Jest and related libraries to capture and compare screenshots, highlighting tools like jest-image-snapshot for this purpose. A key challenge with visual tests is achieving consistent results across different environments due to varying rendering processes, an issue that containerization with Docker can solve by producing uniform test outcomes. The article also discusses integrating these tests into Continuous Integration (CI) systems using GitHub Actions, ensuring reliable deployment processes. Though Storybook offers visual regression testing capabilities, the article argues that Jest provides a simpler, less complex solution, ultimately encouraging developers to implement visual regression testing for more comprehensive and reliable software development practices.