[quality] GroupLinkStatus's plural drift wording and invalid-checkedAt guard have no end-to-end coverage #1094

Finding

src/components/GroupLinkStatus/index.js is the lowest-covered file in the
end-to-end report — 60.00% of regions — with four uncovered regions at lines
7, 23, 32 and 33. Three of them are reachable; the fourth is a different class.

 5 function formatDate(isoDate) {
 6   const parsed = new Date(isoDate);
 7   if (Number.isNaN(parsed.getTime())) return null;      // uncovered
...
23   const stale = (groupsData?.groups || []).filter(      // uncovered: the `|| []` fallback
...
28       {checkedAt && <p>Upstream group links last verified on {checkedAt}.</p>}
...
32           {stale.length === 1 ? 'has an' : 'have'}      // uncovered: the plural arm
33           archived or unreachable upstream {stale.length === 1 ? 'repository' : 'repositories'}

tests/e2e/fixtures/data/community-groups.json appends exactly one archived
group, so the coverage build always renders the singular grammar and the plural
arms at lines 32 and 33 are never taken. Line 7 needs a checkedAt that does
not parse, which the real file never has.

Two groups drifting at once is an ordinary shape — data/community-groups.json
has two groups today and npm run check:community-group-links sets archived /
reachable on both independently — and it is the shape the overlay cannot
currently produce.

Line 23's || [] is a defensive fallback over a field that is always present;
it is not in scope here, and reaching it would require clearing groups
entirely, which would stop the warning rendering at all.

Evidence and provenance

• Unit — covered. tests/group-link-status.test.mjs already drives all
  three arms directly: "two drifted groups are listed together with plural
  wording", "an unparseable checkedAt drops the verification line rather than
  rendering 'Invalid Date'" and "missing groups data renders without
  throwing". npm run test:unit:coverage
  (TZ=UTC node tests/tools/coverage-report.mjs, node v26.10.0) run locally at
  8afaa67 reports no sub-100% region for this file.
• E2E — not covered. CI artifact e2e-coverage, id 11348560988, from run
  37317061554,
  workflow Validate repository, job End-to-end coverage, main at
  8afaa67 — the same revision as the unit run. report.json:
  {"file":"src/components/GroupLinkStatus/index.js","regions":10,"coveredRegions":6,"regionPercent":60,"uncoveredRegions":[7,23,32,33]}.
• Covered by unit tests but not end-to-end tests, so priority 2 under the
  coverage-evidence rules.

Recommendation

Both arms have to be reachable in one Playwright run, so this is a variant-build
case, exactly like AwardsTimeline's provenance paragraph: the ordinary
coverage build keeps the singular grammar and the rendered checkedAt line,
and a second build renders the arms beside them.

Add tests/e2e/fixtures/data-variants/community-groups.json:

{
  "description": "Appends a second drifted group and makes checkedAt unparseable, so GroupLinkStatus renders the plural arms of its drift warning (src/components/GroupLinkStatus/index.js lines 32-33) and takes formatDate's Number.isNaN guard at line 7. The ordinary coverage overlay appends exactly one archived group, so that build renders the singular grammar and the verification line; both arms are only reachable in one Playwright run because the variant build is served beside the real one.",
  "set": {
    "checkedAt": "not a timestamp"
  },
  "append": {
    "groups": [
      {
        "slug": "e2e-coverage-unreachable",
        "name": "Second Coverage Fixture User Group",
        "repository": "https://github.com/cncf/endusers",
        "archived": false,
        "reachable": false
      }
    ]
  }
}

The variant directory is additive and applies second
(tests/tools/e2e-data-fixtures.cjs:100-107), so this layers on top of the
existing tests/e2e/fixtures/data/community-groups.json and the variant build
sees two drifted groups.

This change also requires an edit to a currently-pinned unit test

tests/e2e-data-fixtures.test.mjs:170-173 uses community-groups.json as the
contrast case for awards.json — it asserts the file has no variant
overlay:

const groups = join(DATA_DIR, 'community-groups.json');
assert.deepEqual(overlayPathsFor(groups, { E2E_COVERAGE_VARIANT: '1' }), [
  join(FIXTURE_DIR, 'community-groups.json'),
]);

Adding the overlay above makes that assertion false. It must be updated to
expect both overlay paths, and another data file with no variant overlay
(members.json) should take over the contrast role so the test keeps proving
that the variant directory is consulted only when it has something to say.

• tests/e2e/fixtures/data-variants/community-groups.json added as above
• tests/e2e-data-fixtures.test.mjs:170-173 updated to expect both overlays, with members.json as the new contrast case
• A spec pairs /community with /e2e-coverage-variant/community, asserting the singular grammar and the verification line on the first and the plural grammar with both group names on the second
• src/components/GroupLinkStatus/index.js lines 7, 32 and 33 leave the uncovered-region list

Coordination

No PR is opened for this, deliberately. The required edit to
tests/e2e-data-fixtures.test.mjs collides with two open hold-gated PRs that
are already editing that file — #1034 (lines 178-215) and #1078 (lines 78-91) —
and the natural home for the spec, tests/e2e/data-variants.spec.js, is being
edited by #1034 in the same hunks a new case would take. This should be picked
up once #1034 and #1078 land.

Distinct from #1092, which is MetricsDashboard's single-point Sparkline arm
and touches no file in common; its PR (#1093) adds a separate spec file and only
edits tests/e2e/fixtures/data-variants/metrics.json.

Priority

• Impact: medium (the lowest-covered file in the e2e report; three reachable regions)
• Effort: low

🐝 Hive Agent: quality | Instance: hosted-available-lke648397-260827-5n31 | SHA: bd7842d

— hive: agent=quality backend=copilot model=claude-opus-5 copilot=1.0.88