# Resource-limit tests (NFT-RES-LIM-01..06)

**Task**: AZ-573
**Name**: Resource-limit tests
**Description**: Implement xUnit tests for the 6 resource-limit scenarios: sustained-load process memory, single-file upload boundary, outbox depth under broker outage, disk usage by `images_dir`, concurrent SSE subscribers, migration on cold-start cost.
**Complexity**: 3 points
**Dependencies**: AZ-564 (test infrastructure)
**Component**: Blackbox Tests → Resource Limits
**Tracker**: jira
**Epic**: AZ-563

## Scenarios Covered

| Test ID | Source | What it asserts |
|---------|--------|-----------------|
| NFT-RES-LIM-01 | `_docs/02_document/tests/resource-limit-tests.md` | Sustained-load process memory stays within configured envelope. |
| NFT-RES-LIM-02 | same | Single-file upload boundary — 1, 10, 50, 100, 256, 512 MB. Uses `LargePayloadFixture` synthetic JPEGs. |
| NFT-RES-LIM-03 | same | Outbox queue depth bounded under broker outage. Depth never exceeds documented ceiling for ≥ 30 min run. |
| NFT-RES-LIM-04 | same | Disk usage by `images_dir` over many distinct uploads. Stays under documented HW-02 budget. |
| NFT-RES-LIM-05 | same | Concurrent SSE subscribers — process-memory boundary. N concurrent subscribers don't push memory past envelope. |
| NFT-RES-LIM-06 | same | Migration on cold-start cost. Time-to-`/health=200` from cold start within the documented boot budget. |

## System Under Test Boundary

- HTTP only.
- Memory + disk metrics read from `docker stats` (out-of-band, runner-only). Marked `[Trait("docker_stats", "true")]`.
- NFT-RES-LIM-02 uses `LargePayloadFixture` to generate synthetic JPEGs at runtime; never committed to repo.
- NFT-RES-LIM-03 long-running (30 min smoke variant); the nightly profile runs the full 30 min, the standard profile runs a 5-min smoke proxy.
- NFT-RES-LIM-05 spawns N parallel SSE subscribers via `Parallel.For` + per-subscriber `HttpClient`.

## Acceptance Criteria

**AC-1: Every scenario passes per its spec.**

**AC-2: Smoke vs nightly profile distinction**
Given a profile environment variable `E2E_RUN_PROFILE=functional` (default),
When NFT-RES-LIM-03 runs,
Then it executes a 5-min smoke proxy (not the 30-min full run); under `E2E_RUN_PROFILE=performance`, it runs the full 30 min.

**AC-3: Memory + disk readings have measurement uncertainty noted**
Given `docker stats` is the measurement source,
When the test records a memory or disk reading,
Then the result includes a tolerance margin (e.g., ± 50 MB for memory, ± 100 MB for disk) per the documented `results_report.md` tolerance.

## Constraints

- AAA pattern.
- `[Trait("traces_to", "AC-N-03, AC-N-05, HW-02, HW-03")]` plus per-test specific traces.
- Long-running tests `[Fact(Timeout = ?)]` per documented duration; never hang the runner.