[CLAUDE] Tests: Plan C task 1-3 — Service per-NV Allow* test catch-up (S21 t4-t5 Mig 28-29)

14 test cover 3 helper sửa lớn S21 t4-t5 (test-after UAT backlog):

Task 1+2 — PurchaseEvaluationWorkflowServiceReturnModeTests.cs (7 test):
- ApplyReturnModeAsync Drafter allowed/denied/admin bypass (3 test mode flag)
- OneLevel happy path (peer review chain in same Step)
- OneLevel admin bypass (override disabled flag)
- skipToFinal Drafter allowed/denied/admin bypass (3 test per-user F2)

Task 3 — PurchaseEvaluationDraftGuardTests.cs (7 test):
- Drafter scope: DangSoanThao + TraLai → return (2 test)
- F3 Approver scope: ChoDuyet + flag on + actor match → return
- F3 Approver scope: ChoDuyet + flag off → ConflictException
- F3 Approver scope: ChoDuyet + flag on + actor mismatch → ForbiddenException
- Admin bypass ChoDuyet + flag off → return
- DaDuyet any caller → ConflictException (terminal phase)

InternalsVisibleTo: expose PurchaseEvaluationDraftGuard internal helper cho test.

Finding: skipToFinal Service mutate Phase=ChoDuyet TRƯỚC validate user flag.
Throw chặn SaveChanges nên DB không persist nhưng in-memory dirty. Note trong
test — không refactor scope catch-up (defer S22+).

Verify:
- dotnet test SolutionErp.slnx — 103/103 PASS (58 Domain + 45 Infra)
  Δ: 89 → 103 (+14: ReturnMode 7 + Guard 7)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/Backend/SolutionErp.Application/SolutionErp.Application.csproj

@@ -18,4 +18,9 @@
     <Nullable>enable</Nullable>
   </PropertyGroup>
 
+  <ItemGroup>
+    <!-- Expose internal helpers (e.g. PurchaseEvaluationDraftGuard) cho test project -->
+    <InternalsVisibleTo Include="SolutionErp.Infrastructure.Tests" />
+  </ItemGroup>
+
 </Project>