Testing & TDD
Visual Regression at Scale
Visual Regression at Scale
This lesson adds advanced coverage to Testing & TDD based on the official documentation and practical production work.
Focus for this lesson: baselines, thresholds, review flows, and stable screenshots.
Learning Goals
- Understand the core idea and when to use it.
- Apply it in a real project without breaking security or performance.
- Connect it to tests, documentation, and monitoring when needed.
Practical Example
await expect(page).toHaveScreenshot("dashboard.png")
Documentation reference: Playwright visual comparisons docs.
Professional Implementation Steps
- Review boundaries and responsibilities before writing code.
- Build a small example and then apply it to a real feature.
- Add a test or smoke check that proves the behavior.
- Document the impact on maintenance and deployment.
Hands-on Practice
Apply this topic to an existing page, API, or component, then review the result for maintainability, security, performance, and user experience.
Production addition: do not judge success only by running the example. Judge it by how clear, testable, and maintainable the decision is.
Avoid copying documentation patterns blindly. Tie every option to a clear project reason.
Summary
Add this topic to your toolbox as an engineering decision that can be explained, tested, and reviewed.