testing-perf

name: testing-perf license: MIT compatibility: "Claude Code 2.1.183+." description: Performance and load testing patterns — k6 load tests, Locust stress tests, pytest execution optimization (xdist parallel, plugins), test type classification, and performance benchmarking. Use when writing load tests, optimizing test execution speed, or setting up pytest infrastructure. tags: [testing, performance, k6, locust, pytest, load-testing, benchmarking] context: fork agent: test-generator version: 2.1.0 author: OrchestKit user-invocable: false disable-model-invocation: false complexity: medium persuasion-type: reference targets:

• library: "k6" version: ">=1.0.0"
• library: "locust" version: ">=2.40.0" metadata: category: document-asset-creation allowed-tools:
• Read
• Glob
• Grep
• WebFetch
• WebSearch

Performance & Load Testing Patterns

Focused skill for performance testing, load testing, and pytest execution optimization. Covers k6, Locust, pytest-xdist parallel execution, custom plugins, and test type classification.

Quick Reference

k6 Quick Start

Set up a load test with thresholds and staged ramp-up:

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 state
    { duration: '30s', target: 0 },   // Ramp down
  ],
  thresholds: {
    http_req_duration: ['p(95)<500'],  // 95th percentile under 500ms
    http_req_failed: ['rate<0.01'],    // Less than 1% error rate
  },
};

export default function () {
  const res = http.get('http://localhost:8000/api/health');
  check(res, {
    'status is 200': (r) => r.status === 200,
    'response time < 200ms': (r) => r.timings.duration < 200,
  });
  sleep(1);
}

Run: k6 run --out json=results.json tests/load/api.js

k6 v1.0+ (May 2025) — what changed

• Native TypeScript: k6 run tests/load/api.ts — no compilation step needed.
• Auto extension provisioning: k6 run pulls required extensions automatically; manual xk6 build is superseded for most workflows.
• Browser module import: import browser from 'k6/browser' — the old k6/experimental/browser path was removed in v0.52+. Any generated code using /experimental/ will fail.
• OTLP output built in: k6 run --out experimental-opentelemetry=... — stream results straight to your tracing backend.

import http from 'k6/http'
import browser from 'k6/browser'
import { check } from 'k6'

export const options = { vus: 5, duration: '30s' }

export default async function () {
  const page = await browser.newPage()
  await page.goto('https://example.com')
  check(page, { 'title present': async p => (await p.title()).length > 0 })
  await page.close()
}

Performance Test Types

pytest Parallel Execution

Speed up test suites with pytest-xdist:

# pyproject.toml
[tool.pytest.ini_options]
addopts = ["-n", "auto", "--dist", "loadscope"]
markers = [
    "slow: marks tests as slow",
    "smoke: critical path tests for CI/CD",
]

# Run with parallel workers and coverage
pytest -n auto --dist loadscope --cov=app --cov-report=term-missing --maxfail=3

# CI fast path — skip slow tests
pytest -m "not slow" -n auto

# Debug mode — single worker
pytest -n 0 -x --tb=long

Worker Database Isolation

When running parallel tests with databases, isolate per worker:

@pytest.fixture(scope="session")
def db_engine(worker_id):
    db_name = f"test_db_{worker_id}" if worker_id != "master" else "test_db"
    engine = create_engine(f"postgresql://localhost/{db_name}")
    yield engine
    engine.dispose()

Key Thresholds

Decision Guide

Related Skills

• ork:testing-unit — Unit testing patterns, pytest fixtures
• ork:testing-e2e — End-to-end performance testing with Playwright
• ork:performance — Core Web Vitals and optimization patterns