ci(lighthouse): stop lhci reading the form factor as a CLI flag

lhci treats every LHCI_* environment variable as a command-line option, so
LHCI_PRESET=mobile reached `lhci assert` as an invalid --preset and failed
both jobs after the audits had run. Use LIGHTHOUSE_FORM_FACTOR instead.

Also upload the reports: upload-artifact v4+ skips dot-directories such as
.lighthouseci unless include-hidden-files is set.

.github/workflows/tests.yml

@@ -86,7 +86,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        preset: [mobile, desktop]
+        form-factor: [mobile, desktop]
     steps:
       - uses: actions/checkout@v5
       - uses: actions/setup-node@v5
@@ -97,13 +97,16 @@ jobs:
       # The homepage streams public stats from the database, so audit against a real stack.
       - run: npx supabase start
       - run: npm run test:lighthouse
+        # Not LHCI_*: lhci reads any LHCI_ variable as a CLI flag (LHCI_PRESET became `--preset`).
         env:
-          LHCI_PRESET: ${{ matrix.preset }}
+          LIGHTHOUSE_FORM_FACTOR: ${{ matrix.form-factor }}
       - uses: actions/upload-artifact@v6
         if: always()
         with:
-          name: lighthouse-${{ matrix.preset }}
+          name: lighthouse-${{ matrix.form-factor }}
           path: .lighthouseci/
+          # upload-artifact v4+ skips dot-directories unless told otherwise.
+          include-hidden-files: true
           if-no-files-found: ignore
       - if: always()
         run: npx supabase stop

README.md

@@ -45,7 +45,7 @@ The test suite is split by responsibility so a failure points to the correct lay
 - `lighthouserc.cjs` audits the public pages with Lighthouse CI (`npm run test:lighthouse`, which
   builds and serves the Node output). PRs fail if Performance, Accessibility, Best Practices or SEO
   drops below 90, or if LCP, TBT, CLS, script, stylesheet or total transfer size exceeds its budget.
-  CI runs it with both the mobile and desktop profiles (`LHCI_PRESET=desktop`).
+  CI runs it with both the mobile and desktop profiles (`LIGHTHOUSE_FORM_FACTOR=desktop`).
 - `tests/bdd/features/performance.feature` holds time budgets for signed-in pages Lighthouse can't
   reach: opening a Pokédex and switching between it and the Pokédex list.
 

lighthouserc.cjs

@@ -1,8 +1,10 @@
 // Lighthouse CI: `npm run test:lighthouse` builds the Node adapter output, serves it and audits the
 // public pages. Any category below 90 fails the run (and so the PR).
-// Set LHCI_PRESET=desktop to audit with the desktop profile; the default is Lighthouse's mobile
+// Set LIGHTHOUSE_FORM_FACTOR=desktop to audit with the desktop profile; the default is Lighthouse's
-// profile (slow 4G + CPU throttling), which is the stricter of the two.
+// mobile profile (slow 4G + CPU throttling), which is the stricter of the two. The variable must not
-const preset = process.env.LHCI_PRESET === 'desktop' ? 'desktop' : undefined;
+// start with LHCI_: lhci treats those as CLI flags, so LHCI_PRESET was passed to `lhci assert` as
+// an invalid `--preset`.
+const preset = process.env.LIGHTHOUSE_FORM_FACTOR === 'desktop' ? 'desktop' : undefined;
 
 module.exports = {
 	ci: {