performance-testing

Performance Testing Skill (k6)

Expertise: k6 load/stress/soak tests, SLO baselines, threshold gates, bottleneck identification, CI integration.

Test Type Selection

Load test    → Validate behavior at expected production traffic (steady state)
Stress test  → Find breaking point; gradually increase load until failure
Soak test    → Detect memory leaks / degradation over time (run 1-8 hours)
Spike test   → Simulate sudden traffic burst (10x normal in seconds)

k6 Load Test Template

// tests/performance/create-order.k6.js
import http from 'k6/http';
import { check, sleep } from 'k6';
import { Trend, Counter } from 'k6/metrics';

const orderCreationDuration = new Trend('order_creation_duration');
const failedOrders = new Counter('failed_orders');

export const options = {
  stages: [
    { duration: '2m', target: 50 },   // Ramp up
    { duration: '5m', target: 50 },   // Steady state
    { duration: '2m', target: 200 },  // Stress
    { duration: '2m', target: 0 },    // Ramp down
  ],
  thresholds: {
    // These are your SLO gates — CI fails if breached
    http_req_duration: ['p(95)<500', 'p(99)<2000'],
    http_req_failed: ['rate<0.01'],       // < 1% errors
    order_creation_duration: ['p(99)<3000'],
  },
};

const BASE_URL = __ENV.BASE_URL || 'http://localhost:8000';

export function setup() {
  // Create test auth token once before load test
  const res = http.post(`${BASE_URL}/auth/token`, JSON.stringify({
    username: '[email protected]', password: __ENV.TEST_PASSWORD,
  }), { headers: { 'Content-Type': 'application/json' } });
  return { token: res.json('access_token') };
}

export default function (data) {
  const headers = {
    'Authorization': `Bearer ${data.token}`,
    'Content-Type': 'application/json',
  };

  const start = Date.now();
  const res = http.post(
    `${BASE_URL}/api/v1/orders`,
    JSON.stringify({ items: [{ product_id: 'prod_123', quantity: 1 }] }),
    { headers },
  );

  orderCreationDuration.add(Date.now() - start);

  const ok = check(res, {
    'status is 201': (r) => r.status === 201,
    'has order id': (r) => r.json('id') !== undefined,
  });

  if (!ok) failedOrders.add(1);

  sleep(1);  // Think time between requests
}