performance-testing

# Performance Testing

Validate system behavior under load.

## k6 Load Test (JavaScript)

```javascript
import http from 'k6/http';
import { check, sleep } from 'k6';

export const options = {
  stages: [
    { duration: '30s', target: 20 },  // Ramp up
    { duration: '1m', target: 20 },   // Steady
    { duration: '30s', target: 0 },   // Ramp down
  ],
  thresholds: {
    http_req_duration: ['p(95)<500'],  // 95% under 500ms
    http_req_failed: ['rate<0.01'],    // <1% errors
  },
};

export default function () {
  const res = http.get('http://localhost:8500/api/health');

  check(res, {
    'status is 200': (r) => r.status === 200,
    'response time < 200ms': (r) => r.timings.duration < 200,
  });

  sleep(1);
}
```

## Locust Load Test (Python)

```python
from locust import HttpUser, task, between

class APIUser(HttpUser):
    wait_time = between(1, 3)

    @task(3)
    def get_analyses(self):
        self.client.get("/api/analyses")

    @task(1)
    def create_analysis(self):
        self.client.post(
            "/api/analyses",
            json={"url": "https://example.com"}
        )

    def on_start(self):
        """Login before tasks."""
        self.client.post("/api/auth/login", json={
            "email": "test@example.com",
            "password": "password"
        })
```

## Test Types

### Load Test
```javascript
// Normal expected load
export const options = {
  vus: 50,           // Virtual users
  duration: '5m',    // Duration
};
```

### Stress Test
```javascript
// Find breaking point
export const options = {
  stages: [
    { duration: '2m', target: 100 },
    { duration: '2m', target: 200 },
    { duration: '2m', target: 300 },
    { duration: '2m', target: 400 },
  ],
};
```

### Spike Test
```javascript
// Sudden traffic surge
export const options = {
  stages: [
    { duration: '10s', target: 10 },
    { duration: '1s', target: 1000 },  // Spike!
    { duration: '3m', target: 1000 },
    { duration: '10s', target: 10 },
  ],
};
```