References — fw-12 Testing Library, Browser Automation, and DevTools

Primary sources first. Read the real implementation after you have written yours, never before.

Testing Library

dom-testing-library source — read queries/ and role-helpers.js; the accessibility-tree-first query design is the whole idea
Guiding principles — "the more your tests resemble the way your software is used…"
user-event — why fireEvent is not enough. This matters more than it looks: fe-01 (sibling project) measured that synthetic dispatch does not interleave microtasks between listeners the way real input does, and fe-04 (sibling project) measured that setting .value never triggers tooShort. A synthetic harness has different semantics from production.
aria-query — the role/attribute data behind getByRole

Chrome DevTools Protocol — every measurement in the fe-* track is built directly on this. Domains worth knowing: Runtime, Performance, HeapProfiler, Accessibility, Emulation, Input.
Playwright — read packages/playwright-core/src/server/ for how a trusted-input abstraction is built over CDP
WebDriver BiDi — the standards-track successor; worth tracking
Puppeteer — a thinner CDP wrapper, easier to read for protocol mechanics

DevTools frontend source — it is a web application, and you can debug it with itself
Contributing to DevTools
Extending DevTools — custom panels via extension APIs

fe-01 … fe-06 src/ (sibling project) — 22 working examples of CDP-driven measurement
bi-12 — Debugging & tracing — the same protocol from the browser-internals side
fe-32/fe-33 — UI and E2E testing (planned)

When a claim here proves stale, record it in PROGRESS.md section 7.