test: adds test for ProxyClass

This test timed out before implementing the changes.

tests/client/test_proxy_class.py

@@ -0,0 +1,22 @@
+import asyncio
+from unittest.mock import AsyncMock, call, patch
+
+import pytest
+
+from pydase import components
+from pydase.client.proxy_class import ProxyClass
+
+
+@pytest.mark.asyncio
+async def test_serialize_fallback_inside_event_loop() -> None:
+    loop = asyncio.get_running_loop()
+    mock_sio = AsyncMock()
+    proxy = ProxyClass(sio_client=mock_sio, loop=loop, reconnect=lambda: None)
+
+    with patch.object(
+        components.DeviceConnection, "serialize", return_value={"value": {}}
+    ) as mock_fallback:
+        result = proxy.serialize()
+
+    mock_fallback.assert_has_calls(calls=[call(), call()])
+    assert isinstance(result, dict)