Seeds 120 UPLOADED docs with a deterministic date spread and runs DocumentService.searchDocuments against a Testcontainers Postgres, not a Mockito mock. Five cases: 1. First page returns exactly page_size items + correct totalElements 2. Last partial page returns the tail slice (offset 100 → 20 items) 3. Page beyond last returns empty content, totalElements still 120 4. SENDER sort path slices in-memory + reports correct total 5. Different pages return disjoint document id sets Closes the integration-coverage gap between the Mockito unit tests and the full Spec→Pageable→Page→DTO path that unit tests can't exercise. Runs in ~87 s against the shared Testcontainers instance. (#316) Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>