Salvaged from PR #977 onto current main. Preserves the MCP stdio command resolution and improved error diagnostics, with deterministic regression tests for the npx/node PATH cases. Co-authored-by: kshitij <82637225+kshitijk4poor@users.noreply.github.com>
87 lines
3.1 KiB
Python
87 lines
3.1 KiB
Python
import asyncio
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import os
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from types import SimpleNamespace
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from unittest.mock import AsyncMock, MagicMock, patch
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import pytest
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from tools.mcp_tool import MCPServerTask, _format_connect_error, _resolve_stdio_command
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def test_resolve_stdio_command_falls_back_to_hermes_node_bin(tmp_path):
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node_bin = tmp_path / "node" / "bin"
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node_bin.mkdir(parents=True)
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npx_path = node_bin / "npx"
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npx_path.write_text("#!/bin/sh\nexit 0\n", encoding="utf-8")
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npx_path.chmod(0o755)
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with patch("tools.mcp_tool.shutil.which", return_value=None), \
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patch.dict("os.environ", {"HERMES_HOME": str(tmp_path)}, clear=False):
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command, env = _resolve_stdio_command("npx", {"PATH": "/usr/bin"})
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assert command == str(npx_path)
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assert env["PATH"].split(os.pathsep)[0] == str(node_bin)
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def test_resolve_stdio_command_respects_explicit_empty_path():
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seen_paths = []
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def _fake_which(_cmd, path=None):
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seen_paths.append(path)
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return None
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with patch("tools.mcp_tool.shutil.which", side_effect=_fake_which):
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command, env = _resolve_stdio_command("python", {"PATH": ""})
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assert command == "python"
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assert env["PATH"] == ""
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assert seen_paths == [""]
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def test_format_connect_error_unwraps_exception_group():
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error = ExceptionGroup(
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"unhandled errors in a TaskGroup",
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[FileNotFoundError(2, "No such file or directory", "node")],
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)
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message = _format_connect_error(error)
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assert "missing executable 'node'" in message
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def test_run_stdio_uses_resolved_command_and_prepended_path(tmp_path):
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node_bin = tmp_path / "node" / "bin"
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node_bin.mkdir(parents=True)
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npx_path = node_bin / "npx"
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npx_path.write_text("#!/bin/sh\nexit 0\n", encoding="utf-8")
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npx_path.chmod(0o755)
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mock_session = MagicMock()
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mock_session.initialize = AsyncMock()
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mock_session.list_tools = AsyncMock(return_value=SimpleNamespace(tools=[]))
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mock_stdio_cm = MagicMock()
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mock_stdio_cm.__aenter__ = AsyncMock(return_value=(object(), object()))
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mock_stdio_cm.__aexit__ = AsyncMock(return_value=False)
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mock_session_cm = MagicMock()
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mock_session_cm.__aenter__ = AsyncMock(return_value=mock_session)
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mock_session_cm.__aexit__ = AsyncMock(return_value=False)
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async def _test():
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with patch("tools.mcp_tool.shutil.which", return_value=None), \
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patch.dict("os.environ", {"HERMES_HOME": str(tmp_path), "PATH": "/usr/bin", "HOME": str(tmp_path)}, clear=False), \
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patch("tools.mcp_tool.StdioServerParameters") as mock_params, \
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patch("tools.mcp_tool.stdio_client", return_value=mock_stdio_cm), \
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patch("tools.mcp_tool.ClientSession", return_value=mock_session_cm):
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server = MCPServerTask("srv")
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await server.start({"command": "npx", "args": ["-y", "pkg"], "env": {"PATH": "/usr/bin"}})
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call_kwargs = mock_params.call_args.kwargs
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assert call_kwargs["command"] == str(npx_path)
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assert call_kwargs["env"]["PATH"].split(os.pathsep)[0] == str(node_bin)
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await server.shutdown()
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asyncio.run(_test())
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