[Eugene (OEvgeny)]

Changelog Entry

Not required, development only.

Description

Avatar middleware tests failed a few pixels off the snapshot in about 3-5% of runs, e.g. 2 shards in the last CI run of #5873. When the avatar image is not available at first paint, the browser repaints its area later, and the anti-aliased rounded edges around it come out slightly different.

Design

Layout is identical in failing runs, only anti-aliased edges differ. With images preloaded, 0 failures in 300 local runs, down from about 3-5%.

Specific Changes

• Added testHelpers.preloadImages(), which loads and decodes images, and keeps them available until they are rendered

• Avatar middleware tests preload the avatar images before rendering

• I have added tests and executed them locally

• I have updated CHANGELOG.md

• I have updated documentation

Review Checklist

This section is for contributors to review your work.

• Accessibility reviewed (tab order, content readability, alt text, color contrast)
• Browser and platform compatibilities reviewed
• CSS styles reviewed (minimal rules, no z-index)
• Documents reviewed (docs, samples, live demo)
• Internationalization reviewed (strings, unit formatting)
• package.json and package-lock.json reviewed
• Security reviewed (no data URIs, check for nonce leak)
• Tests reviewed (coverage, legitimacy)

[Copilot]

🟢 Approval recommended

Static review found no blocking issues in these narrow test-only changes; browser tests were not rerun during review.

No open issues 🎉

What changed in this PR

Stabilizes avatar middleware snapshots by ensuring avatar images are decoded before rendering. Changes are limited to test infrastructure and tests.

Changes:

• Adds and exports preloadImages() to load, decode, and retain images.
• Updates ten avatar middleware tests to preload both avatars before rendering.

File	Description
packages/​test/​page-object/​src/​globals/​testHelpers/​preloadImages.js	Adds image preloading helper.
packages/​test/​page-object/​src/​globals/​testHelpers/​index.js	Exports the helper.
tests/​html2/​middleware/​avatar/​useBuildRenderAvatarCallback.html	Preloads avatars for callback tests.
tests/​html2/​middleware/​avatar/​renderProxy.html	Preloads avatars for proxy tests.
tests/​html2/​middleware/​avatar/​polymiddleware/​decorate.html	Preloads avatars for decoration tests.
tests/​html2/​middleware/​avatar/​polymiddleware/​changing.html	Preloads avatars for middleware-change tests.
tests/​html2/​middleware/​avatar/​polymiddleware/​addOrReplace.html	Preloads avatars for replacement tests.
tests/​html2/​middleware/​avatar/​legacyAvatarMiddleware/​styleOptions.html	Preloads avatars for legacy styling tests.
tests/​html2/​middleware/​avatar/​legacyAvatarMiddleware/​decorate.html	Preloads avatars for legacy decoration tests.
tests/​html2/​middleware/​avatar/​legacyAvatarMiddleware/​changing.html	Preloads avatars for legacy middleware-change tests.
tests/​html2/​middleware/​avatar/​legacyAvatarMiddleware/​addOrReplace.html	Preloads avatars for legacy replacement tests.
tests/​html2/​middleware/​avatar/​backwardCompatibility.html	Preloads avatars for compatibility tests.

_{Review effort: Balanced}