E2E Behavior Validation for Frontend Modifications

Core Principle: Test Product Behavior, Not UI States

CRITICAL: Tests must verify that product features WORK correctly, not just that UI elements render.

What NOT to test (UI States):

• ❌ "Dropdown opens when clicked"
• ❌ "Modal appears after button click"
• ❌ "Loading spinner shows during request"
• ❌ "Form fields are visible"
• ❌ "Sidebar collapses"

What TO test (Product Behavior):