user-system/docs/evidence/ops/2026-03-28/quality/COVERAGE_REMEDIATION_20260328-140215.md

2026-03-28 Q-004 Coverage Remediation Pass 21

Scope

• Continue strict Q-004 closure work after Pass 20.
• Fully close the shared error-model hotspot in:
  • frontend/admin/src/lib/errors/AppError.ts
  • frontend/admin/src/lib/errors/index.ts
• Re-verify closure through targeted error-module tests and full frontend validation.

Changes

Frontend

• Added dedicated error-module coverage in:
  • frontend/admin/src/lib/errors/AppError.test.ts
• Newly covered behavior includes:
  • AppError constructor defaults
  • explicit option handling with cause
  • backend response to error-type mapping
  • factory helpers for auth / forbidden / validation / network errors
  • isAuthError, isForbidden, and isNetworkError
  • user-facing message mapping across all error types
  • isAppError
  • getErrorMessage
  • isFormValidationError

Backend

• No backend code changes were required in this pass.

Verified Commands

cd D:\project\frontend\admin
npm.cmd run test:run -- src/lib/errors/AppError.test.ts
npm.cmd run lint
npm.cmd run build
npm.cmd run test:coverage

Results

Frontend coverage

• Overall:
  • statements 93.07%
  • branches 81.35%
  • functions 90.32%
  • lines 93.26%
• Target areas:
  • src/lib/errors/AppError.ts: statements 100%, branches 100%, functions 100%, lines 100%
  • src/lib/errors/index.ts: statements 100%, branches 100%, functions 100%, lines 100%

Validation outcomes

• Full frontend coverage run now completes with:
  • 51 passing test files
  • 238 passing tests
• The required sequential frontend validation path passed:
  • test:run -- src/lib/errors/AppError.test.ts
  • lint
  • build
  • test:coverage

Validation Notes

• 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 cannot be hidden.

Real Conclusion

• src/lib/errors/AppError.ts is no longer an open Q-004 gap.
• src/lib/errors/index.ts 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/pages/admin/ImportExportPage/ImportExportPage.tsx
  • src/pages/NotFoundPage/NotFoundPage.tsx
  • src/lib/hooks/useBreadcrumbs.ts
  • src/app/providers/ThemeProvider.tsx
  • the post-summary jsdom AggregateError coverage-noise hygiene issue