TESTING.md

Room State Synchronization Test

To test the fix for the room state synchronization issue:

Test Steps:

1. Start the frontend: Run npm run dev in the frontend directory

2. Open first browser window:

   • Navigate to http://localhost:3000
   • Create a new room (e.g., "test-room")
   • Enter username (e.g., "user1")
   • Join the room

3. Add some content:

   • Type some code in the editor (e.g., "console.log('Hello from user1');")
   • Switch to whiteboard and draw something
   • Switch back to editor and add more code

4. Open second browser window:

   • Navigate to http://localhost:3000
   • Join the SAME room ("test-room")
   • Enter different username (e.g., "user2")

5. Verify state synchronization:

   • The second user should immediately see:
     • The code that user1 typed
     • The whiteboard drawings from user1
     • The correct language setting

6. Test real-time sync:

   • User2 types in editor → User1 should see changes
   • User2 draws on whiteboard → User1 should see drawings
   • User1 makes changes → User2 should see them

Expected Behavior:

• ✅ New users get current room state immediately
• ✅ No more "empty state overwrites existing work" bug
• ✅ Real-time synchronization works for both editor and whiteboard
• ✅ No infinite update loops

Backend Changes Made:

• Added RoomState struct to store room state
• Store code, language, and whiteboard elements per room
• Send current state to new users in WELCOME message
• Update room state when changes are broadcast

Frontend Changes Made:

• Added initialization tracking to prevent immediate overwrites
• Whiteboard waits for WELCOME message before sending updates
• Code editor waits for initialization before sending changes
• Both components handle initial state from WELCOME message

Debug Info:

Check browser console for:

• "WebSocket URL:" - should show correct URL
• "RECEIVED: action 'WELCOME'" - should show state object
• "SENDING: action 'CODE_CHANGE'" - should only appear after initialization