test(streamable-http): cover closed-send helper

Author: Jianke LIN

tests/client/test_streamable_http.py

@@ -36,6 +36,7 @@
     MAX_RECONNECTION_ATTEMPTS,
     RequestContext,
     StreamableHTTPTransport,
+    _send_or_ignore_closed,
     streamable_http_client,
 )
 from mcp.server import Server
@@ -198,6 +199,18 @@ async def test_sse_message_ignores_closed_read_stream() -> None:
     assert complete is True
 
 
+@pytest.mark.anyio
+async def test_send_or_ignore_closed_reports_delivery_status() -> None:
+    read_stream_writer, read_stream = create_context_streams[SessionMessage | Exception](1)
+    message = SessionMessage(JSONRPCResponse(jsonrpc="2.0", id=1, result={}))
+
+    async with read_stream_writer, read_stream:
+        assert await _send_or_ignore_closed(read_stream_writer, message) is True  # pyright: ignore[reportPrivateUsage]
+        assert await read_stream.receive() == message
+        await read_stream.aclose()
+        assert await _send_or_ignore_closed(read_stream_writer, message) is False  # pyright: ignore[reportPrivateUsage]
+
+
 @pytest.mark.anyio
 async def test_post_request_merges_per_message_metadata_headers() -> None:
     """`ClientMessageMetadata.headers` on a `SessionMessage` are merged into the outgoing POST headers