test(adk): restore SystemMessage between tests

Author: contextablemark

typescript-sdk/integrations/adk-middleware/python/tests/conftest.py

@@ -0,0 +1,20 @@
+"""Shared pytest fixtures for ADK middleware tests."""
+
+from __future__ import annotations
+
+import pytest
+
+from ag_ui.core import SystemMessage as CoreSystemMessage
+
+import ag_ui_adk.adk_agent as adk_agent_module
+
+
+@pytest.fixture(autouse=True)
+def restore_system_message_class():
+    """Ensure every test starts and ends with the real SystemMessage type."""
+
+    adk_agent_module.SystemMessage = CoreSystemMessage
+    try:
+        yield
+    finally:
+        adk_agent_module.SystemMessage = CoreSystemMessage