Simplify stdio child process cleanup tests

Remove test-only WindowsProcessWrapper class and platform-specific logic
by leveraging the existing production _create_platform_compatible_process()
function. This eliminates ~20 lines of duplicate functionality and ensures
tests use the same robust cross-platform code paths as production.

Also remove redundant uv.index setting from pyproject.toml since uv
defaults to PyPI anyway.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: felixweinberger

pyproject.toml

@@ -111,8 +111,6 @@ members = ["examples/servers/*"]
 [tool.uv.sources]
 mcp = { workspace = true }
 
-[[tool.uv.index]]
-url = "https://pypi.org/simple"
 
 [tool.pytest.ini_options]
 log_cli = true

tests/client/test_stdio.py

@@ -1,6 +1,5 @@
 import os
 import shutil
-import subprocess
 import sys
 import tempfile
 import textwrap
@@ -12,6 +11,7 @@
 from mcp.client.session import ClientSession
 from mcp.client.stdio import (
     StdioServerParameters,
+    _create_platform_compatible_process,
     stdio_client,
 )
 from mcp.shared.exceptions import McpError
@@ -28,27 +28,6 @@ def escape_path_for_python(path: str) -> str:
     return repr(path.replace("\\", "/"))
 
 
-class WindowsProcessWrapper:
-    """Minimal wrapper for subprocess.Popen to work with anyio-style process interface."""
-
-    def __init__(self, popen):
-        self.pid = popen.pid
-        self._popen = popen
-        # Add popen attribute for compatibility with _terminate_process_with_children
-        self.popen = popen
-
-    async def wait(self):
-        while self._popen.poll() is None:
-            await anyio.sleep(0.1)
-        return self._popen.returncode
-
-    def terminate(self):
-        self._popen.terminate()
-
-    def kill(self):
-        self._popen.kill()
-
-
 @pytest.mark.anyio
 @pytest.mark.skipif(tee is None, reason="could not find tee command")
 async def test_stdio_context_manager_exiting():
@@ -423,15 +402,8 @@ async def test_stdio_client_child_process_cleanup():
 
         print("\nStarting child process termination test...")
 
-        # Start the parent process directly with process group
-        if sys.platform == "win32":
-            # Windows: Don't use CREATE_NEW_PROCESS_GROUP as it isolates the process
-            # Instead, let it inherit the parent's console which allows taskkill /T to work
-            popen = subprocess.Popen([sys.executable, "-c", parent_script])
-            proc = WindowsProcessWrapper(popen)
-        else:
-            # Unix: Use start_new_session for process group creation
-            proc = await anyio.open_process([sys.executable, "-c", parent_script], start_new_session=True)
+        # Start the parent process
+        proc = await _create_platform_compatible_process(sys.executable, ["-c", parent_script])
 
         # Wait for processes to start
         await anyio.sleep(0.5)
@@ -537,15 +509,8 @@ async def test_stdio_client_nested_process_tree():
             """
         )
 
-        # Start parent process directly
-        if sys.platform == "win32":
-            # Windows: Don't use CREATE_NEW_PROCESS_GROUP as it isolates the process
-            # Instead, let it inherit the parent's console which allows taskkill /T to work
-            popen = subprocess.Popen([sys.executable, "-c", parent_script])
-            proc = WindowsProcessWrapper(popen)
-        else:
-            # Unix: Use start_new_session for process group creation
-            proc = await anyio.open_process([sys.executable, "-c", parent_script], start_new_session=True)
+        # Start the parent process
+        proc = await _create_platform_compatible_process(sys.executable, ["-c", parent_script])
 
         # Let all processes start
         await anyio.sleep(1.0)
@@ -629,14 +594,7 @@ def handle_term(sig, frame):
         )
 
         # Start the parent process
-        if sys.platform == "win32":
-            # Windows: Don't use CREATE_NEW_PROCESS_GROUP as it isolates the process
-            # Instead, let it inherit the parent's console which allows taskkill /T to work
-            popen = subprocess.Popen([sys.executable, "-c", parent_script])
-            proc = WindowsProcessWrapper(popen)
-        else:
-            # Unix: Use start_new_session for process group creation
-            proc = await anyio.open_process([sys.executable, "-c", parent_script], start_new_session=True)
+        proc = await _create_platform_compatible_process(sys.executable, ["-c", parent_script])
 
         # Let child start writing
         await anyio.sleep(0.5)