add test

libs/langgraph/tests/test_config_async.py

@@ -1,7 +1,8 @@
 import pytest
-from langchain_core.callbacks import AsyncCallbackManager
+from langchain_core.callbacks import AsyncCallbackManager, BaseCallbackHandler
 
 from langgraph._internal._config import get_async_callback_manager_for_config
+from langgraph.graph import StateGraph
 
 pytestmark = pytest.mark.anyio
 
@@ -17,3 +18,21 @@ def test_new_async_manager_merges_tags_with_config() -> None:
     config = {"callbacks": None, "tags": ["a"]}
     manager = get_async_callback_manager_for_config(config, tags=["b"])
     assert manager.inheritable_tags == ["a", "b"]
+
+
+async def test_with_config_callbacks_preserved_in_astream_events() -> None:
+    class TrackingCallback(BaseCallbackHandler):
+        def __init__(self) -> None:
+            self.called = False
+
+        def on_chain_start(self, *args, **kwargs) -> None:
+            self.called = True
+
+    builder = StateGraph(dict)
+    builder.add_node("node", lambda state: state)
+    builder.add_edge("__start__", "node")
+    cb = TrackingCallback()
+    graph = builder.compile().with_config({"callbacks": [cb]})
+    async for _ in graph.astream_events({}, version="v2"):
+        pass
+    assert cb.called