# Resilience Tests

### NFT-RES-01: Loader service outage after engine initialization

**Summary**: Verify that detections continue working when the Loader service goes down after the engine is already loaded.
**Traces to**: RESTRICT-ENV-1

**Preconditions**:
- Engine is initialized (model already downloaded)

**Fault injection**:
- Stop mock-loader service

**Steps**:

| Step | Action | Expected Behavior |
|------|--------|------------------|
| 1 | Stop mock-loader | — |
| 2 | `POST /detect` with small-image | 200 OK — detection succeeds (engine already in memory) |
| 3 | `GET /health` | `aiAvailability` remains "Enabled" |

**Pass criteria**: Detection continues to work. Health status remains stable. No errors from loader unavailability.

---

### NFT-RES-02: Annotations service outage during async detection

**Summary**: Verify that async detection completes and delivers SSE events even when Annotations service is down.
**Traces to**: RESTRICT-ENV-2

**Preconditions**:
- Engine is initialized
- SSE client connected

**Fault injection**:
- Stop mock-annotations mid-processing

**Steps**:

| Step | Action | Expected Behavior |
|------|--------|------------------|
| 1 | Start async detection: `POST /detect/test-media-res01` | `{"status": "started"}` |
| 2 | After first few SSE events, stop mock-annotations | — |
| 3 | Continue listening to SSE | Events continue arriving. Annotations POST failures are silently caught |
| 4 | Wait for completion | Final `AIProcessed` event received |

**Pass criteria**: Detection pipeline completes fully. SSE delivery is unaffected. No crash or 500 errors.

---

### NFT-RES-03: Engine initialization retry after transient loader failure

**Summary**: Verify that if model download fails on first attempt, a subsequent detection request retries initialization.
**Traces to**: AC-EL-2

**Preconditions**:
- Fresh service (engine not initialized)

**Fault injection**:
- Mock-loader returns 503 on first model request, then recovers

**Steps**:

| Step | Action | Expected Behavior |
|------|--------|------------------|
| 1 | Configure mock-loader to fail first request | — |
| 2 | `POST /detect` with small-image | Error (503 or 422) |
| 3 | Configure mock-loader to succeed | — |
| 4 | `POST /detect` with small-image | 200 OK — engine initializes on retry |

**Pass criteria**: Second detection succeeds after loader recovers. System does not permanently lock into error state.

---

### NFT-RES-04: Service restart with in-memory state loss

**Summary**: Verify that after a service restart, all in-memory state (_active_detections, _event_queues) is cleanly reset.
**Traces to**: RESTRICT-OP-5, RESTRICT-OP-6

**Preconditions**:
- Previous detection may have been in progress

**Fault injection**:
- Restart detections container

**Steps**:

| Step | Action | Expected Behavior |
|------|--------|------------------|
| 1 | Restart detections container | — |
| 2 | `GET /health` | Returns `aiAvailability: "None"` (fresh start) |
| 3 | `POST /detect/any-media-id` | Accepted (no stale _active_detections blocking it) |

**Pass criteria**: No stale state from previous session. All endpoints functional after restart.