[Eugene (OEvgeny)]

Adds end-to-end coverage for #5967: an activity updated out of (or into) a part grouping renders once.

Changelog Entry

Not required, test-only change.

Description

#5967 fixed the store so an activity updated into, out of, or between part groupings renders once; its tests are unit tests of upsert(). These html2 tests cover the rendered transcript, including the avatar and checkmark rows that re-render on a group change (#5966's useLogicalGroupKey()), and fail before #5967 with the development "graph has 3 activities, Redux has 4 activities" error.

Specific Changes

• part-grouping/leaveGroup.html: snapshots 1–2, step 2 leaves the group: once, own avatar, no checkmark
• part-grouping/joinGroup.html: snapshots 1–2, step 2 joins the group: once, between steps 1 and 3

• I have added tests and executed them locally
• I have added .changelog/<PR#>-<slug>.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)

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