crxboxPlaywright, but extension-aware

A lightweight toolkit for end-to-end testing Chrome (MV3) extensions. Zero runtime dependencies — Playwright is a peer you provide.

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API Reference

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Real extension, real browser

Drives the actual installed extension in a real Chromium — not mocked chrome.* APIs. Catches the bugs mocks hide.

First-class extension surfaces

Helpers for the popup, content-script UI (Shadow DOM / iframes / injection timing), the MV3 service worker (including forced restart), storage, and the extension ID / URLs.

A thin layer on Playwright

You keep all of Playwright — locators, assertions, traces, parallelism. crxbox just ships the extension-specific parts so you stop hand-rolling that 150-line fixtures file.

AI coding agent friendly

Ships a built-in SKILL.md — a token-efficient guide designed for AI coding agents, covering the full API surface, canonical patterns, and failure codes in one file so agents write correct tests without scanning source.