Introduction

A Playwright harness for Firefox WebExtension integration tests.

Launch an isolated Firefox profile, install multiple extensions from directories or packed XPIs, inspect their background contexts, evaluate page code, activate browser/page actions, and access the underlying Firefox RDP client from one fixture set.

Start here

• Getting started — install the package and create fixtures.
• Fixtures and evaluation — use the extensions collection, background and isolated evaluators, and raw rdp client.
• Actions and popups — open browser actions and page actions in headless Firefox.
• RDP access — use the FirefoxRDP client for low-level protocol operations.
• Local mappings and WebRequest — serve static fixtures and test fulfilled-response events without an HTTP server.
• API reference — browse the public TypeScript API and generated declarations.

About compatibility

Firefox RDP is an internal, version-sensitive protocol. The harness targets the Firefox revision supplied by Playwright and applies the required compatibility patch during global setup. Run the integration suite against the same Firefox build used in CI.