E2E Testing

Overview

Browser E2E validates full user journeys. This file owns selectors, auto-waiting, network interception, POM, browser flakiness, and trace/video debugging (Playwright-first, Cypress noted where it differs). E2E is the tip of the pyramid — keep it thin and reserve it for critical paths; push logic down to unit/integration (loom-test-strategy). For test-double taxonomy and AAA see loom-testing.

Framework choice

Default to Playwright for new suites: true multi-browser (incl. WebKit/Safari), multi-tab/origin, out-of-process network interception, built-in parallelism and trace viewer, and non-JS bindings (Python/.NET/Java). Choose Cypress only when the team is already invested or wants its live time-travel debugger; its in-browser model limits multi-tab, cross-origin, and true WebKit. Selenium/Puppeteer: legacy or Chrome-only automation, not greenfield E2E.

npm init playwright@latest         # scaffolds config + CI + browsers