Files
mcp-python-sdk/tests/client/test_session.py
2025-06-11 11:45:50 +02:00

498 lines
18 KiB
Python

from typing import Any
import anyio
import pytest
import mcp.types as types
from mcp.client.session import DEFAULT_CLIENT_INFO, ClientSession
from mcp.shared.context import RequestContext
from mcp.shared.message import SessionMessage
from mcp.shared.session import RequestResponder
from mcp.shared.version import SUPPORTED_PROTOCOL_VERSIONS
from mcp.types import (
LATEST_PROTOCOL_VERSION,
ClientNotification,
ClientRequest,
Implementation,
InitializedNotification,
InitializeRequest,
InitializeResult,
JSONRPCMessage,
JSONRPCNotification,
JSONRPCRequest,
JSONRPCResponse,
ServerCapabilities,
ServerResult,
)
@pytest.mark.anyio
async def test_client_session_initialize():
client_to_server_send, client_to_server_receive = anyio.create_memory_object_stream[SessionMessage](1)
server_to_client_send, server_to_client_receive = anyio.create_memory_object_stream[SessionMessage](1)
initialized_notification = None
async def mock_server():
nonlocal initialized_notification
session_message = await client_to_server_receive.receive()
jsonrpc_request = session_message.message
assert isinstance(jsonrpc_request.root, JSONRPCRequest)
request = ClientRequest.model_validate(
jsonrpc_request.model_dump(by_alias=True, mode="json", exclude_none=True)
)
assert isinstance(request.root, InitializeRequest)
result = ServerResult(
InitializeResult(
protocolVersion=LATEST_PROTOCOL_VERSION,
capabilities=ServerCapabilities(
logging=None,
resources=None,
tools=None,
experimental=None,
prompts=None,
),
serverInfo=Implementation(name="mock-server", version="0.1.0"),
instructions="The server instructions.",
)
)
async with server_to_client_send:
await server_to_client_send.send(
SessionMessage(
JSONRPCMessage(
JSONRPCResponse(
jsonrpc="2.0",
id=jsonrpc_request.root.id,
result=result.model_dump(by_alias=True, mode="json", exclude_none=True),
)
)
)
)
session_notification = await client_to_server_receive.receive()
jsonrpc_notification = session_notification.message
assert isinstance(jsonrpc_notification.root, JSONRPCNotification)
initialized_notification = ClientNotification.model_validate(
jsonrpc_notification.model_dump(by_alias=True, mode="json", exclude_none=True)
)
# Create a message handler to catch exceptions
async def message_handler(
message: RequestResponder[types.ServerRequest, types.ClientResult] | types.ServerNotification | Exception,
) -> None:
if isinstance(message, Exception):
raise message
async with (
ClientSession(
server_to_client_receive,
client_to_server_send,
message_handler=message_handler,
) as session,
anyio.create_task_group() as tg,
client_to_server_send,
client_to_server_receive,
server_to_client_send,
server_to_client_receive,
):
tg.start_soon(mock_server)
result = await session.initialize()
# Assert the result
assert isinstance(result, InitializeResult)
assert result.protocolVersion == LATEST_PROTOCOL_VERSION
assert isinstance(result.capabilities, ServerCapabilities)
assert result.serverInfo == Implementation(name="mock-server", version="0.1.0")
assert result.instructions == "The server instructions."
# Check that the client sent the initialized notification
assert initialized_notification
assert isinstance(initialized_notification.root, InitializedNotification)
@pytest.mark.anyio
async def test_client_session_custom_client_info():
client_to_server_send, client_to_server_receive = anyio.create_memory_object_stream[SessionMessage](1)
server_to_client_send, server_to_client_receive = anyio.create_memory_object_stream[SessionMessage](1)
custom_client_info = Implementation(name="test-client", version="1.2.3")
received_client_info = None
async def mock_server():
nonlocal received_client_info
session_message = await client_to_server_receive.receive()
jsonrpc_request = session_message.message
assert isinstance(jsonrpc_request.root, JSONRPCRequest)
request = ClientRequest.model_validate(
jsonrpc_request.model_dump(by_alias=True, mode="json", exclude_none=True)
)
assert isinstance(request.root, InitializeRequest)
received_client_info = request.root.params.clientInfo
result = ServerResult(
InitializeResult(
protocolVersion=LATEST_PROTOCOL_VERSION,
capabilities=ServerCapabilities(),
serverInfo=Implementation(name="mock-server", version="0.1.0"),
)
)
async with server_to_client_send:
await server_to_client_send.send(
SessionMessage(
JSONRPCMessage(
JSONRPCResponse(
jsonrpc="2.0",
id=jsonrpc_request.root.id,
result=result.model_dump(by_alias=True, mode="json", exclude_none=True),
)
)
)
)
# Receive initialized notification
await client_to_server_receive.receive()
async with (
ClientSession(
server_to_client_receive,
client_to_server_send,
client_info=custom_client_info,
) as session,
anyio.create_task_group() as tg,
client_to_server_send,
client_to_server_receive,
server_to_client_send,
server_to_client_receive,
):
tg.start_soon(mock_server)
await session.initialize()
# Assert that the custom client info was sent
assert received_client_info == custom_client_info
@pytest.mark.anyio
async def test_client_session_default_client_info():
client_to_server_send, client_to_server_receive = anyio.create_memory_object_stream[SessionMessage](1)
server_to_client_send, server_to_client_receive = anyio.create_memory_object_stream[SessionMessage](1)
received_client_info = None
async def mock_server():
nonlocal received_client_info
session_message = await client_to_server_receive.receive()
jsonrpc_request = session_message.message
assert isinstance(jsonrpc_request.root, JSONRPCRequest)
request = ClientRequest.model_validate(
jsonrpc_request.model_dump(by_alias=True, mode="json", exclude_none=True)
)
assert isinstance(request.root, InitializeRequest)
received_client_info = request.root.params.clientInfo
result = ServerResult(
InitializeResult(
protocolVersion=LATEST_PROTOCOL_VERSION,
capabilities=ServerCapabilities(),
serverInfo=Implementation(name="mock-server", version="0.1.0"),
)
)
async with server_to_client_send:
await server_to_client_send.send(
SessionMessage(
JSONRPCMessage(
JSONRPCResponse(
jsonrpc="2.0",
id=jsonrpc_request.root.id,
result=result.model_dump(by_alias=True, mode="json", exclude_none=True),
)
)
)
)
# Receive initialized notification
await client_to_server_receive.receive()
async with (
ClientSession(
server_to_client_receive,
client_to_server_send,
) as session,
anyio.create_task_group() as tg,
client_to_server_send,
client_to_server_receive,
server_to_client_send,
server_to_client_receive,
):
tg.start_soon(mock_server)
await session.initialize()
# Assert that the default client info was sent
assert received_client_info == DEFAULT_CLIENT_INFO
@pytest.mark.anyio
async def test_client_session_version_negotiation_success():
"""Test successful version negotiation with supported version"""
client_to_server_send, client_to_server_receive = anyio.create_memory_object_stream[SessionMessage](1)
server_to_client_send, server_to_client_receive = anyio.create_memory_object_stream[SessionMessage](1)
async def mock_server():
session_message = await client_to_server_receive.receive()
jsonrpc_request = session_message.message
assert isinstance(jsonrpc_request.root, JSONRPCRequest)
request = ClientRequest.model_validate(
jsonrpc_request.model_dump(by_alias=True, mode="json", exclude_none=True)
)
assert isinstance(request.root, InitializeRequest)
# Verify client sent the latest protocol version
assert request.root.params.protocolVersion == LATEST_PROTOCOL_VERSION
# Server responds with a supported older version
result = ServerResult(
InitializeResult(
protocolVersion="2024-11-05",
capabilities=ServerCapabilities(),
serverInfo=Implementation(name="mock-server", version="0.1.0"),
)
)
async with server_to_client_send:
await server_to_client_send.send(
SessionMessage(
JSONRPCMessage(
JSONRPCResponse(
jsonrpc="2.0",
id=jsonrpc_request.root.id,
result=result.model_dump(by_alias=True, mode="json", exclude_none=True),
)
)
)
)
# Receive initialized notification
await client_to_server_receive.receive()
async with (
ClientSession(
server_to_client_receive,
client_to_server_send,
) as session,
anyio.create_task_group() as tg,
client_to_server_send,
client_to_server_receive,
server_to_client_send,
server_to_client_receive,
):
tg.start_soon(mock_server)
result = await session.initialize()
# Assert the result with negotiated version
assert isinstance(result, InitializeResult)
assert result.protocolVersion == "2024-11-05"
assert result.protocolVersion in SUPPORTED_PROTOCOL_VERSIONS
@pytest.mark.anyio
async def test_client_session_version_negotiation_failure():
"""Test version negotiation failure with unsupported version"""
client_to_server_send, client_to_server_receive = anyio.create_memory_object_stream[SessionMessage](1)
server_to_client_send, server_to_client_receive = anyio.create_memory_object_stream[SessionMessage](1)
async def mock_server():
session_message = await client_to_server_receive.receive()
jsonrpc_request = session_message.message
assert isinstance(jsonrpc_request.root, JSONRPCRequest)
request = ClientRequest.model_validate(
jsonrpc_request.model_dump(by_alias=True, mode="json", exclude_none=True)
)
assert isinstance(request.root, InitializeRequest)
# Server responds with an unsupported version
result = ServerResult(
InitializeResult(
protocolVersion="2020-01-01", # Unsupported old version
capabilities=ServerCapabilities(),
serverInfo=Implementation(name="mock-server", version="0.1.0"),
)
)
async with server_to_client_send:
await server_to_client_send.send(
SessionMessage(
JSONRPCMessage(
JSONRPCResponse(
jsonrpc="2.0",
id=jsonrpc_request.root.id,
result=result.model_dump(by_alias=True, mode="json", exclude_none=True),
)
)
)
)
async with (
ClientSession(
server_to_client_receive,
client_to_server_send,
) as session,
anyio.create_task_group() as tg,
client_to_server_send,
client_to_server_receive,
server_to_client_send,
server_to_client_receive,
):
tg.start_soon(mock_server)
# Should raise RuntimeError for unsupported version
with pytest.raises(RuntimeError, match="Unsupported protocol version"):
await session.initialize()
@pytest.mark.anyio
async def test_client_capabilities_default():
"""Test that client capabilities are properly set with default callbacks"""
client_to_server_send, client_to_server_receive = anyio.create_memory_object_stream[SessionMessage](1)
server_to_client_send, server_to_client_receive = anyio.create_memory_object_stream[SessionMessage](1)
received_capabilities = None
async def mock_server():
nonlocal received_capabilities
session_message = await client_to_server_receive.receive()
jsonrpc_request = session_message.message
assert isinstance(jsonrpc_request.root, JSONRPCRequest)
request = ClientRequest.model_validate(
jsonrpc_request.model_dump(by_alias=True, mode="json", exclude_none=True)
)
assert isinstance(request.root, InitializeRequest)
received_capabilities = request.root.params.capabilities
result = ServerResult(
InitializeResult(
protocolVersion=LATEST_PROTOCOL_VERSION,
capabilities=ServerCapabilities(),
serverInfo=Implementation(name="mock-server", version="0.1.0"),
)
)
async with server_to_client_send:
await server_to_client_send.send(
SessionMessage(
JSONRPCMessage(
JSONRPCResponse(
jsonrpc="2.0",
id=jsonrpc_request.root.id,
result=result.model_dump(by_alias=True, mode="json", exclude_none=True),
)
)
)
)
# Receive initialized notification
await client_to_server_receive.receive()
async with (
ClientSession(
server_to_client_receive,
client_to_server_send,
) as session,
anyio.create_task_group() as tg,
client_to_server_send,
client_to_server_receive,
server_to_client_send,
server_to_client_receive,
):
tg.start_soon(mock_server)
await session.initialize()
# Assert that capabilities are properly set with defaults
assert received_capabilities is not None
assert received_capabilities.sampling is None # No custom sampling callback
assert received_capabilities.roots is None # No custom list_roots callback
@pytest.mark.anyio
async def test_client_capabilities_with_custom_callbacks():
"""Test that client capabilities are properly set with custom callbacks"""
client_to_server_send, client_to_server_receive = anyio.create_memory_object_stream[SessionMessage](1)
server_to_client_send, server_to_client_receive = anyio.create_memory_object_stream[SessionMessage](1)
received_capabilities = None
async def custom_sampling_callback(
context: RequestContext["ClientSession", Any],
params: types.CreateMessageRequestParams,
) -> types.CreateMessageResult | types.ErrorData:
return types.CreateMessageResult(
role="assistant",
content=types.TextContent(type="text", text="test"),
model="test-model",
)
async def custom_list_roots_callback(
context: RequestContext["ClientSession", Any],
) -> types.ListRootsResult | types.ErrorData:
return types.ListRootsResult(roots=[])
async def mock_server():
nonlocal received_capabilities
session_message = await client_to_server_receive.receive()
jsonrpc_request = session_message.message
assert isinstance(jsonrpc_request.root, JSONRPCRequest)
request = ClientRequest.model_validate(
jsonrpc_request.model_dump(by_alias=True, mode="json", exclude_none=True)
)
assert isinstance(request.root, InitializeRequest)
received_capabilities = request.root.params.capabilities
result = ServerResult(
InitializeResult(
protocolVersion=LATEST_PROTOCOL_VERSION,
capabilities=ServerCapabilities(),
serverInfo=Implementation(name="mock-server", version="0.1.0"),
)
)
async with server_to_client_send:
await server_to_client_send.send(
SessionMessage(
JSONRPCMessage(
JSONRPCResponse(
jsonrpc="2.0",
id=jsonrpc_request.root.id,
result=result.model_dump(by_alias=True, mode="json", exclude_none=True),
)
)
)
)
# Receive initialized notification
await client_to_server_receive.receive()
async with (
ClientSession(
server_to_client_receive,
client_to_server_send,
sampling_callback=custom_sampling_callback,
list_roots_callback=custom_list_roots_callback,
) as session,
anyio.create_task_group() as tg,
client_to_server_send,
client_to_server_receive,
server_to_client_send,
server_to_client_receive,
):
tg.start_soon(mock_server)
await session.initialize()
# Assert that capabilities are properly set with custom callbacks
assert received_capabilities is not None
assert received_capabilities.sampling is not None # Custom sampling callback provided
assert isinstance(received_capabilities.sampling, types.SamplingCapability)
assert received_capabilities.roots is not None # Custom list_roots callback provided
assert isinstance(received_capabilities.roots, types.RootsCapability)
assert received_capabilities.roots.listChanged is True # Should be True for custom callback