E2E Tests for a Multi-Step Checkout Flow

Problem/Feature Description

An e-commerce app has a multi-step checkout flow: cart review, shipping address, payment, and order confirmation. Write Playwright E2E tests that cover the happy path (completing checkout) and key error cases.

The app runs on http://localhost:3000 and has these pages:

• /cart -- shows items in cart with quantities and a "Proceed to Checkout" button
• /checkout/shipping -- shipping address form (name, address, city, zip) with a "Continue" button
• /checkout/payment -- payment form (card number, expiry, CVV) with a "Place Order" button
• /checkout/confirmation -- shows order number and summary

The app has a REST API:

• POST /api/orders -- creates an order (returns 201 with order ID)
• GET /api/orders/:id -- retrieves order details

Output Specification

Produce:

• playwright.config.ts -- Playwright configuration
• e2e/checkout.spec.ts -- E2E test file for the checkout flow
• package.json -- with @playwright/test dependency listed

You may create additional files if needed for good test organization (e.g., page objects, fixtures).