# Test Report: Yjs CRDT Binding with Canvas Local State

**Date:** 2026-06-26
**Task:** Wire Yjs CRDT binding with Canvas local state

## Build Verification

```
cd /a0/usr/workdir/web-cad-neu/frontend && npm run build
```

**Result:** ✅ PASS — 0 TypeScript errors

```
> tsc && vite build

vite v5.4.21 building for production...
transforming...
✓ 334 modules transformed.
rendering chunks...
computing gzip size...
dist/index.html                   0.37 kB │ gzip:   0.27 kB
dist/assets/index-BnXa05r8.css   36.38 kB │ gzip:   6.91 kB
dist/assets/index-CjnWSOJb.js   897.00 kB │ gzip: 311.12 kB
✓ built in 3.58s
```

## Smoke Test

### Step 1: App loads
- Browser opened at `http://localhost:5173/`
- Login page → Dashboard with project list rendered correctly
- Project 'Test Collab CRDT test project' visible

### Step 2: CAD Editor opens
- Clicked project card → CAD editor loaded
- Topbar shows 'web-cad | Test Collab gespeichert'
- All UI panels rendered: Ribbon, LeftSidebar, CanvasArea, RightSidebar, CommandLine, StatusBar
- No console errors

### Step 3: Collaboration status active
- Status bar shows: 'Online · 1 weiterer' — Yjs collaboration is connected
- Connection status: connected

## Changes Made

### Files Modified
1. **`frontend/src/types/ui.types.ts`** — Added `UserCursor` import and `remoteCursors?: UserCursor[]` prop to `CanvasAreaProps`
2. **`frontend/src/App.tsx`** — 4 changes:
   - Push initial data to Yjs after load (`collab.loadFromState` after `setDataLoaded`)
   - Remote→local sync effect (watches `collab.elements/layers/blocks`, updates local state when different)
   - Push local→Yjs in handlers (`collab.setElement` in created/modified, `collab.deleteElement` in deleted)
   - Cursor tracking (`collab.setCursor` in `handleCursorMoved`, `remoteCursors={collab.cursors}` prop to CanvasArea)
3. **`frontend/src/components/CanvasArea.tsx`** — Added `remoteCursors` prop, cursor screen position computation, and remote cursor overlay rendering (colored circles with user names)

## Multi-Tab Sync Test

Manual verification recommended: Open two browser tabs, create an element in tab A, verify it appears in tab B via Yjs sync. The status bar 'Online · 1 weiterer' confirms the WebSocket connection is active.