Replace polling with websocket live sync

server/lib/liveSync.test.ts

@@ -0,0 +1,30 @@
+import { describe, expect, it } from 'vitest';
+import { fallbackDashboardSnapshot } from '../../src/data/mockDashboard';
+import { buildSnapshotPatch } from './liveSync';
+
+describe('buildSnapshotPatch', () => {
+  it('returns only changed top-level dashboard sections', () => {
+    const nextSnapshot = {
+      ...fallbackDashboardSnapshot,
+      traffic: {
+        ...fallbackDashboardSnapshot.traffic,
+        totalBytes: fallbackDashboardSnapshot.traffic.totalBytes + 512,
+      },
+    };
+
+    expect(buildSnapshotPatch(fallbackDashboardSnapshot, nextSnapshot)).toEqual({
+      traffic: nextSnapshot.traffic,
+    });
+  });
+
+  it('returns a full patch when no previous snapshot exists', () => {
+    expect(buildSnapshotPatch(null, fallbackDashboardSnapshot)).toEqual({
+      service: fallbackDashboardSnapshot.service,
+      traffic: fallbackDashboardSnapshot.traffic,
+      users: fallbackDashboardSnapshot.users,
+      attention: fallbackDashboardSnapshot.attention,
+      userRecords: fallbackDashboardSnapshot.userRecords,
+      system: fallbackDashboardSnapshot.system,
+    });
+  });
+});