Add frontend test coverage with @vitest/coverage-v8

Configure vitest coverage with v8 provider and cobertura reporter.
Add coverage step to CI pipeline that uploads coverage artifact.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: toddaheath

.github/workflows/ci.yml

@@ -98,8 +98,16 @@ jobs:
       - name: TypeScript check
         run: npx tsc --noEmit
 
-      - name: Test
-        run: npm test
+      - name: Test with coverage
+        run: npx vitest run --coverage
+
+      - name: Upload frontend coverage
+        uses: actions/upload-artifact@v7
+        if: always()
+        with:
+          name: frontend-coverage
+          path: src/shed-builder-ui/coverage/coverage.cobertura.xml
+          retention-days: 14
 
       - name: Build
         run: npm run build

src/shed-builder-ui/package-lock.json

@@ -33,6 +33,7 @@
     "@types/react-dom": "^19.2.3",
     "@types/three": "^0.182.0",
     "@vitejs/plugin-react": "^5.1.1",
+    "@vitest/coverage-v8": "^4.0.18",
     "eslint": "^9.39.1",
     "eslint-plugin-react-hooks": "^7.0.1",
     "eslint-plugin-react-refresh": "^0.5.2",

src/shed-builder-ui/package.json

@@ -7,5 +7,11 @@ export default defineConfig({
     environment: 'happy-dom',
     setupFiles: ['./src/test-setup.ts'],
     globals: true,
+    coverage: {
+      provider: 'v8',
+      reporter: ['text', 'cobertura'],
+      include: ['src/**/*.{ts,tsx}'],
+      exclude: ['src/**/*.test.*', 'src/test-setup.ts', 'src/vite-env.d.ts'],
+    },
   },
 })