Simple HTTP MCP Server

from http import HTTPStatus from starlette.testclient import TestClient from http_mcp._transport_types import ProtocolErrorCode from tests.models import DUMMY_SERVER def test_unsupported_content_type() -> None: client = TestClient(DUMMY_SERVER.app) response = client.post( "/mcp", json={"jsonrpc": "2.0", "method": "tools/list", "id": 1}, headers={"Content-Type": "text/plain"}, ) assert response.status_code == HTTPStatus.UNSUPPORTED_MEDIA_TYPE assert response.json() == { "jsonrpc": "2.0", "error": { "code": ProtocolErrorCode.INVALID_PARAMS.value, "message": "Unsupported Media Type: Content-Type must be application/json", }, } def test_unsupported_request_method() -> None: client = TestClient(DUMMY_SERVER.app) response = client.get("/mcp") assert response.status_code == HTTPStatus.METHOD_NOT_ALLOWED assert response.text == "Method Not Allowed" def test_request_body_too_large() -> None: client = TestClient(DUMMY_SERVER.app) response = client.post( "/mcp", json={ "jsonrpc": "2.0", "method": "tools/list", "id": 1, }, content=b"a" * 5 * 1024 * 1024, headers={"Content-Type": "application/json"}, ) assert response.status_code == HTTPStatus.REQUEST_ENTITY_TOO_LARGE assert response.json() == { "jsonrpc": "2.0", "error": { "code": ProtocolErrorCode.INVALID_PARAMS.value, "message": "Request body too large.", }, } def test_parse_error() -> None: client = TestClient(DUMMY_SERVER.app) response = client.post( "/mcp", json={"jsonrpc": "2.0", "method": "tools/list", "id": 1}, content=b"invalid", headers={"Content-Type": "application/json"}, ) assert response.status_code == HTTPStatus.BAD_REQUEST assert response.json() == { "jsonrpc": "2.0", "error": { "code": ProtocolErrorCode.INVALID_PARAMS.value, "message": "Parse error: Invalid body", }, } def test_notification() -> None: client = TestClient(DUMMY_SERVER.app) response = client.post( "/mcp", json={ "jsonrpc": "2.0", "method": "notifications/initialized", }, headers={"Content-Type": "application/json"}, ) assert response.status_code == HTTPStatus.OK assert response.text == "" def test_invalid_message() -> None: client = TestClient(DUMMY_SERVER.app) response = client.post( "/mcp", json={"jsonrpc": "2.0"}, ) assert response.status_code == HTTPStatus.BAD_REQUEST assert response.json() == { "jsonrpc": "2.0", "error": { "code": ProtocolErrorCode.METHOD_NOT_FOUND.value, "message": "Error validating message request", }, }