Testing: Write Tests That Catch Real Bugs

Write, structure, and maintain tests across unit, integration, E2E, accessibility, and performance layers. The goal is tests that catch regressions, document behavior, and run fast in CI - not tests that exist to inflate coverage numbers.

Target versions (September 2026):

• Vitest 5.0.0, Jest 30.5.1
• Playwright 1.63.0, Cypress 16.0.0 (both Vitest and Cypress are major upgrades; review migration notes)
• pytest 9.1.1, pytest-cov 7.1.0
• Go 1.27.1 (testing stdlib, testing/synctest GA)
• Rust 1.98.1 (cargo test, cargo-nextest 0.9.143)
• Testing Library 16.3.3 (@testing-library/react)
• axe-core 4.13.0 (@axe-core/playwright)
• Grafana k6 2.2.0

Security check (2026-09-10): GHSA-2h32-95rg-cppp is critical browser-runner script injection that can expose the API token and lead to local code execution. It affects @vitest/browser >=4.0.17,<4.1.6 and >=5.0.0-beta.0,<5.0.0-beta.3; fixes are 4.1.6 and 5.0.0-beta.3. Keep browser packages aligned with the stable runner and do not open untrusted runner URLs while the server is active.