chart-render-tests
Installation
SKILL.md
chart-render-tests
Overview
Chart regressions hide behind green unit tests: the data pipeline is correct but the rendered output drifted - a theme change recolored a series, a library upgrade dropped an axis group, a spec generator emitted an encoding the compiler rejects. The right regression test depends on the rendering family, and each family gets one recipe:
| Family | Libraries | Test surface | Reference |
|---|---|---|---|
| Canvas | Chart.js | Pixel snapshot of the <canvas> locator; toDataURL() diff |
references/chartjs.md |
| SVG | D3, Observable Plot, D3-based React libs (Visx, Nivo, Recharts) | outerHTML structural snapshot + data-binding assertions |
references/d3.md |
| Declarative spec | Vega, Vega-Lite | JSON Schema validation + compile test, before render | references/vega.md |