Playwright Extension Testing Expert

This skill provides a "gold standard" for browser extension E2E testing, specifically optimized for MV3 and frameworks like WXT. Extensions require unique handling for persistent browser contexts, non-headless modes, and onboarding flows.

Core Mandates

• Non-Headless is Mandatory: Browser extensions do NOT load properly in standard headless mode. Use headless: false .

• Persistent Context: Extensions require launchPersistentContext to maintain state and load correctly.

• XVFB for Linux/CI: Always prefix test commands with xvfb-run -a on Linux/CI to provide a virtual display for the non-headless browser.

• Data-TestId First: Prohibit text-based locators. Always add data-testid to source code if missing.

• Dismiss Onboarding: Every test must dismiss welcome banners/onboarding dialogs before interacting with the UI.

• Complementary Usage: This skill is highly specialized for extensions. For general Playwright best practices (locators, assertions, reporting), you MUST check if playwright-expert or playwright-skill is available and use them in tandem.

Available Boilerplate (Assets)

This skill provides pre-configured boilerplate to jumpstart a project. See the assets/boilerplate/ directory.

• extension-helper.ts : A robust Playwright fixture setup including extensionId discovery and onboarding dismissal.

• playwright.config.ts : The recommended configuration for extension testing.

Workflow: Setting Up a New Project

• Identify Project Structure: Determine where the built extension output is located (e.g., .output/chrome-mv3 ).

• Inject Boilerplate: Use the read_file tool to extract the boilerplate from this skill's assets/ and write them to the target project's tests/e2e/ directory.

• Verify Build Step: Remind the user that extensions must be built BEFORE running E2E tests (yarn build ).

• Run First Test: Use xvfb-run -a playwright test to verify the setup.

Best Practices

The "Dismissal" Loop

Always use the dismissWelcomeBanner helper provided in the boilerplate. Extensions often have multiple layers of onboarding (e.g., "Grant Access", "Get Started").

Storage Management

The boilerplate's extensionId fixture automatically clears chrome.storage.local and chrome.storage.sync before each test. Ensure tests don't assume state exists unless they create it.

Waiting for UI Settle

Extensions can be slower to load than standard web pages. Use a 3000ms settle time after navigation or dismissal.