test(backend): expand helper and media coverage

Backend/tests/sfu-registry.test.ts

@@ -0,0 +1,49 @@
+import { describe, expect, test } from 'bun:test';
+
+import { SfuSessionRegistry } from '../media/sfu/registry';
+
+const buildSession = (streamSessionId: string) => ({
+  streamSessionId,
+  ownerUserId: 'user-1',
+  cameraDeviceId: 'camera-1',
+  requesterDeviceId: 'client-1',
+  state: 'starting' as const,
+  createdAt: '2026-04-16T12:00:00.000Z',
+});
+
+describe('SFU session registry', () => {
+  test('stores and retrieves a session descriptor without internal metadata', () => {
+    const registry = new SfuSessionRegistry();
+    registry.set(buildSession('stream-1'));
+
+    expect(registry.get('stream-1')).toEqual(buildSession('stream-1'));
+  });
+
+  test('returns null when updating a missing session state', () => {
+    const registry = new SfuSessionRegistry();
+
+    expect(registry.updateState('missing-stream', 'live')).toBeNull();
+  });
+
+  test('updates state and lists all registered sessions', () => {
+    const registry = new SfuSessionRegistry();
+    registry.set(buildSession('stream-1'));
+    registry.set({ ...buildSession('stream-2'), cameraDeviceId: 'camera-2' });
+
+    expect(registry.updateState('stream-1', 'live')).toEqual({
+      ...buildSession('stream-1'),
+      state: 'live',
+    });
+
+    expect(registry.list()).toEqual([
+      {
+        ...buildSession('stream-1'),
+        state: 'live',
+      },
+      {
+        ...buildSession('stream-2'),
+        cameraDeviceId: 'camera-2',
+      },
+    ]);
+  });
+});