Multiplayer Testing with E2E Tests

"Server-authoritative code must be validated with actual server connections using E2E tests."

When to Use This Skill

Use for EVERY task marked with serverAuthoritative: true or multiplayerTested: true.

Core Principle: Write Multi-Client E2E Tests

✅ CORRECT APPROACH:

// Write E2E test with multiple browser contexts - YES!
test('server-authoritative movement sync', async ({ browser }) => {
  const context1 = await browser.newContext();
  const context2 = await browser.newContext();
  const page1 = await context1.newPage();
  const page2 = await context2.newPage();