# 2026-03-28 Q-004 Coverage Remediation Pass 15

## Scope

- Continue strict `Q-004` closure work after Pass 14.
- Close the remaining low-cost shell and safety-fallback hotspots in:
  - `frontend/admin/src/app/App.tsx`
  - `frontend/admin/src/app/RootLayout.tsx`
  - `frontend/admin/src/components/common/ErrorBoundary/ErrorBoundary.tsx`
- Re-verify closure through targeted shell tests plus full frontend validation.

## Changes

### Frontend

- Added shell and boundary coverage in:
  - `frontend/admin/src/app/App.test.tsx`
  - `frontend/admin/src/app/RootLayout.test.tsx`
  - `frontend/admin/src/components/common/ErrorBoundary/ErrorBoundary.test.tsx`
- Newly covered behavior includes:
  - app shell wiring between `ErrorBoundary`, `Suspense`, and `RouterProvider`
  - `RootLayout` wrapping the route outlet in `AuthProvider`
  - `ErrorBoundary` child passthrough, custom fallback rendering, default fallback rendering, and reset behavior
- Test hygiene hardening:
  - `ErrorBoundary` tests now suppress expected jsdom uncaught-error noise from deliberate throw cases so the targeted path stays clean

### Backend

- No backend code changes were required in this pass.

## Verified Commands

```powershell
cd D:\project\frontend\admin
npm.cmd run test:run -- src/app/App.test.tsx src/app/RootLayout.test.tsx src/components/common/ErrorBoundary/ErrorBoundary.test.tsx
npm.cmd run lint
npm.cmd run build
npm.cmd run test:coverage
```

## Results

### Frontend coverage

- Overall:
  - statements `89.72%`
  - branches `77.57%`
  - functions `84.48%`
  - lines `90.64%`
- Target areas:
  - `src/app/App.tsx`: statements `100%`, branches `100%`, functions `100%`, lines `100%`
  - `src/app/RootLayout.tsx`: statements `100%`, branches `100%`, functions `100%`, lines `100%`
  - `src/components/common/ErrorBoundary/ErrorBoundary.tsx`: statements `100%`, branches `83.33%`, functions `100%`, lines `100%`

## Validation Notes

- Frontend full coverage now completes with `47` passing test files and `214` passing tests.
- The required sequential frontend validation path passed:
  - `test:run -- src/app/App.test.tsx src/app/RootLayout.test.tsx src/components/common/ErrorBoundary/ErrorBoundary.test.tsx`
  - `lint`
  - `build`
  - `test:coverage`
- The successful frontend coverage run still emits one post-summary jsdom `AggregateError` network-noise line.
  - It does not fail the command.
  - It remains a real validation-hygiene issue and should continue to be tracked honestly.

## Real Conclusion

- `src/app/App.tsx` is no longer an open `Q-004` gap.
- `src/app/RootLayout.tsx` is no longer an open `Q-004` gap.
- `src/components/common/ErrorBoundary/ErrorBoundary.tsx` is no longer an open `Q-004` gap.
- `Q-004` still cannot be honestly declared closed.
- After this pass, the remaining higher-value frontend gaps narrow further to:
  - `src/app/router.tsx`
  - `src/pages/admin/DashboardPage/DashboardPage.tsx`
  - shared page-state coverage such as `src/components/feedback/PageState/PageState.tsx`
  - the post-summary jsdom `AggregateError` coverage-noise hygiene issue