[tmashara]

What

Each shot now records the web font faces it requested, and faces only one side has are reported:

• compact row: fonts -"Inter 600" +"Roboto" under failed (union over the row's widths)
• report.html: fonts … beside the failed-assets line
• results.json: "fonts": { "added": [], "removed": ["Inter 600"] }. added is left only, removed is right only, same as text. Left out when both sides match.
• findings:: fonts -"Inter 600" when it repeats on 2+ differing routes. Clean shots are skipped, so an all-clean run never lists font findings.

A face's name is family plus weight, style and stretch, with normal/400/100% dropped and bold mapped to 700. Surrounding quotes are stripped from the family, since new FontFace("My Face") reports "My Face" where the same @font-face reports My Face. A failed bold face now reads font X 700, which matches the docs' existing font Inter 700 example.

Why

A side that loads a different face (a dropped weight, a renamed family) is easy to miss in the pixels and hard to trace back from a dom property. Naming the face points to the cause directly. Fixes #50.

Scope and choices

• Web fonts only (@font-face and FontFace). System fallbacks never appear in document.fonts, so the issue's +"Arial" can't be produced from there. That would need CDP CSS.getPlatformFontsForNode per text node. The docs say this.
• loading counts as requested. Navigation uses domcontentloaded and the fonts.ready wait is capped at 5s, so a slow face can still be on the wire when it's read. Counting it as missing would give a flaky -.
• A fonts diff alone does not make a shot un-clean. A failed asset does, because the fallback makes the pixels untrustworthy. A face one side loads that paints identical pixels is harmless, and the pixels decide. --rerun-failed behaviour is unchanged.

How tested

• New guard-rail fixture fonts. Both sides use shared/blank.ttf, a 576-byte glyph-less TTF that draws nothing, and only the right also declares a 600 face for the h1. The visual test checks /fonts reports { added: [], removed: ["Blank 600"] } and the row -"Blank 600". It also checks that the shared Blank face and /broken-asset's failing Gone face (present on both sides) produce no fonts.
• Unit tests for pixelFindings: a repeated face on differing routes is a finding, and on clean routes it isn't.
• With src/ reverted, the visual test and the first unit test fail. They pass with the change.
• blank.ttf was generated with fontTools (.notdef only, empty cmap), so it carries no licence. The fixture README says so.
• npm run typecheck, lint, format:check, npm test (340 pass) and npm run test:visual (348 pass) all pass locally.

🤖 Generated with Claude Code