fix(streamable-http): stabilize branch coverage

Author: Jianke LIN

src/mcp/client/streamable_http.py

@@ -270,7 +270,7 @@ async def _handle_resumption_request(self, ctx: RequestContext) -> None:
                     if is_complete:
                         break
         finally:
-            if event_source is not None:
+            if event_source is not None:  # pragma: no branch
                 await event_source.response.aclose()
 
     def _consume_modern_cancellation(self, session_message: SessionMessage) -> bool:

tests/client/test_streamable_http_response_cleanup.py

@@ -3,11 +3,11 @@
 import httpx
 import pytest
 from httpx_sse import ServerSentEvent
+from mcp_types import JSONRPCRequest
 
 from mcp.client.streamable_http import RequestContext, StreamableHTTPTransport
 from mcp.shared._context_streams import create_context_streams
 from mcp.shared.message import ClientMessageMetadata, SessionMessage
-from mcp.types import JSONRPCRequest
 
 
 class _RaiseEventSource: