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IGP-Fan-Reference/docs/AI Gen Docs/test-visual-regression.md
2026-05-31 14:33:58 -04:00

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---
type: Task
status: AI Gen TODO
category: QA
isAgentGenerated: "true"
---
# Test: Visual Regression for Build Calculator Layout
## Description
Use Playwright's built-in screenshot comparison to detect unintended layout changes in the Build Calculator and Database pages.
## Rationale
The Build Calculator renders a complex keyboard-style hotkey viewer with absolute-positioned buttons, a timeline grid, and resin/bank/army sub-panels. A CSS change or component refactor could shift elements, overlap buttons, or misalign the grid. Existing functional tests only check text content and presence of elements — they would not catch a button that renders in the wrong position or overlaps another control.
## Playwright Feature
This test uses **`expect(page).toHaveScreenshot()`** with named snapshots. Playwright compares the current render against a baseline screenshot stored in the repo and reports a diff image on failure.
### Key Benefits
- Catches visual regressions a functional test would miss (position, size, color, overflow).
- Snapshots can be taken at specific viewport sizes (desktop/tablet/mobile) using the `viewport` option.
- Animations (toast fade-out) can be suppressed via `page.evaluate` to freeze the UI before capture.
### Implementation Notes
- Baselines should be generated on first run (`--update-snapshots`) and committed to the repo.
- Use `fullPage: true` to capture the entire scrollable page.
- Mask or remove time-dependent elements (timing counters, toast notifications) before capture to avoid false positives.
- Run in a CI pipeline where the rendering environment (OS, fonts, GPU) is stable.