test: request with bad method crashes task

Author: moldhouse

tests/shared/test_session_handles_error.py

@@ -0,0 +1,42 @@
+from collections.abc import AsyncGenerator
+
+import pytest
+from anyio.streams.memory import MemoryObjectSendStream
+
+from mcp.shared.memory import create_client_server_memory_streams
+from mcp.shared.message import SessionMessage
+from mcp.shared.session import BaseSession
+from mcp.types import ClientNotification, ClientRequest, JSONRPCMessage, JSONRPCRequest
+
+
+@pytest.fixture
+async def client_write() -> (
+    AsyncGenerator[MemoryObjectSendStream[SessionMessage], None]
+):
+    """A stream that allows to write to a running session."""
+    async with create_client_server_memory_streams() as (
+        (_, client_write),
+        (server_read, server_write),
+    ):
+        async with BaseSession(
+            read_stream=server_read,
+            write_stream=server_write,
+            receive_request_type=ClientRequest,
+            receive_notification_type=ClientNotification,
+        ) as _:
+            yield client_write
+
+
+@pytest.mark.anyio
+async def test_session_does_not_raise_error_with_bad_input(
+    client_write: MemoryObjectSendStream[SessionMessage],
+):
+    # Given a running session
+
+    # When the client sends a bad request to the session
+    request = JSONRPCRequest(jsonrpc="2.0", id=1, method="bad_method", params=None)
+    message = SessionMessage(message=JSONRPCMessage(root=request))
+    await client_write.send(message)
+
+    # Then the session can still be talked to
+    await client_write.send(message)