test: cover the docusaurus.config.js and sidebars.js navigation contract (tests/site-config.test.mjs)

[kubestellar-hive]

Test Improvement

Adds tests/site-config.test.mjs (15 tests), the first test to import docusaurus.config.js and sidebars.js. Before this, neither file appeared in the coverage report at all — not at 0%, but never loaded by any test process.

The site's navigation and branding contract lives entirely in those two files and was verified only by a full docusaurus build, which fails late and prints a wall of build errors rather than a named assertion.

What is asserted

• Navbar routes resolve. Every internal to: maps to a real doc route, the blog, or a static file. Route derivation mirrors the docs plugin under routeBasePath: '/' — an explicit frontmatter slug wins, otherwise the path relative to docs/ with index collapsing onto its directory.
• Heading fragments exist. /community/end-user-community#projects-born-at-end-user-organizations is checked against the headings actually present in that doc.
• Sidebar wiring is two-way. Every docSidebar navbar item names a sidebar defined in sidebars.js, and every sidebar is reachable from the navbar. A rename on either side currently fails silently.
• Autogenerated sidebars point at populated directories under docs/.
• Branding assets exist on disk — favicon, navbar.logo.src/srcDark, themeConfig.image, both headTags link hrefs, and theme.customCss.
• onBrokenLinks stays 'throw'. The config carries the comment "Preserve broken-link enforcement; do not weaken." Nothing enforced it until now.
• No two docs claim the same route.
• SITE_URL/BASE_URL overrides flow into url, baseUrl and the JSON-LD logo URL, including the trailing-slash strip. This path only runs for GitHub Pages previews, so it is exercised least often exactly where a mistake is hardest to spot.

Implementation note

docusaurus.config.js is ESM but calls require.resolve() for its plugin list, which Docusaurus supplies through its own loader. The test installs a createRequire shim before importing. That is the one non-obvious part of the file.

Verification

• 15/15 pass; full suite 70/70 (was 55/55). No existing test, helper or fixture is modified.
• docusaurus.config.js and sidebars.js go from absent-from-report to 100% lines; all-files line coverage rises 73.51% → 90.26%.
• Mutation-checked. Six independent mutations of docusaurus.config.js each fail at least one new test: bogus navbar route, onBrokenLinks weakened to 'warn', unknown sidebarId, missing logo asset, dead heading fragment, and removing the trailing-slash strip. The config was restored clean afterwards (git diff empty).
• npx prettier --check clean.

Deliberately out of scope

The editUrl values pointing at castrojo/endusers are being corrected in #245. Asserting the post-fix value here would make this test red on main, so editUrl is not asserted.

Disjointness

Touches exactly one new file, tests/site-config.test.mjs, and no production code. No other open PR touches docusaurus.config.js, sidebars.js, or site navigation. It does not modify tests/helpers.mjs (claimed by #231) and adds no JSX import path (claimed by #229), so it does not overlap the component-test or fixture-sandbox work.

Related Issue

Closes #274 — merging this lands the only deliverable that issue describes, so nothing is left for it to track.

---

Filed by quality agent (hold-gated mode). Human review required.

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

[kubestellar-hive]

Important

Held for human review by the hive's ACMM level gate.

This PR was opened by the "quality" agent while Hive policy required a human checkpoint for that agent. Non-outreach agents are held at ACMM L3–L5; the outreach agent is always held because it publishes project-facing communication.

Hive will automatically remove the hold label once current policy no longer requires a level hold for "quality". If this is an outreach PR, a human must review it and remove the label.