fix a few multisync issues

atlas/tests/test_multiuser.py

@@ -129,8 +129,23 @@ def test_multiuser_load_case_action(client, make_case):
     
     # Manager loads case
     client.force_login(manager)
-    response = client.post(reverse("atlas:multiuser_load_case", kwargs={"session_id": session.id}), data={"case_id": case.pk})
-    assert response.status_code == 200
+    from unittest.mock import patch, MagicMock, AsyncMock
+    with patch("channels.layers.get_channel_layer") as mock_get_channel_layer:
+        mock_layer = MagicMock()
+        mock_layer.group_send = AsyncMock()
+        mock_get_channel_layer.return_value = mock_layer
+        
+        response = client.post(reverse("atlas:multiuser_load_case", kwargs={"session_id": session.id}), data={"case_id": case.pk})
+        assert response.status_code == 200
+        
+        # Verify Channels group_send was called to notify the group about the case change
+        mock_layer.group_send.assert_called_once_with(
+            f"multiuser_{session.id}",
+            {
+                "type": "change_case",
+                "case_id": case.id
+            }
+        )
     
     session.refresh_from_db()
     assert session.active_case == case