Cypress Test Suite for E-commerce Checkout

Create a comprehensive Cypress test suite for an e-commerce checkout flow:

**E-commerce Platform:** {{PLATFORM}}
**Base URL:** {{BASE_URL}}

**Checkout Flow Steps:**
1. Product browsing and selection
2. Add to cart
3. Cart review and modification
4. Guest checkout / User login
5. Shipping information
6. Payment processing
7. Order confirmation

**Test Scenarios:**

**Happy Path:**
- Single item purchase
- Multiple items purchase
- Apply discount codes
- Different payment methods

**Edge Cases:**
- Out of stock handling
- Quantity limits
- Price changes during checkout
- Session timeout
- Network interruptions

**Validation:**
- Required field validation
- Address validation
- Payment validation
- Email format validation

**Generate:**
- Custom Cypress commands
- Page objects/selectors
- Fixtures for test data
- API interception for mocking
- Visual regression setup