change tests

Author: ihrpr

src/mcp/client/stdio/__init__.py

@@ -177,10 +177,14 @@ async def stdin_writer():
             yield read_stream, write_stream
         finally:
             # Clean up process to prevent any dangling orphaned processes
-            if sys.platform == "win32":
-                await terminate_windows_process(process)
-            else:
-                process.terminate()
+            try:
+                if sys.platform == "win32":
+                    await terminate_windows_process(process)
+                else:
+                    process.terminate()
+            except ProcessLookupError:
+                # Process already exited, which is fine
+                pass
             await read_stream.aclose()
             await write_stream.aclose()
 

tests/client/test_stdio.py

@@ -1,17 +1,18 @@
 import shutil
 
 import pytest
-from anyio import fail_after
 
+from mcp.client.session import ClientSession
 from mcp.client.stdio import (
     StdioServerParameters,
     stdio_client,
 )
+from mcp.shared.exceptions import McpError
 from mcp.shared.message import SessionMessage
-from mcp.types import JSONRPCMessage, JSONRPCRequest, JSONRPCResponse
+from mcp.types import CONNECTION_CLOSED, JSONRPCMessage, JSONRPCRequest, JSONRPCResponse
 
 tee: str = shutil.which("tee")  # type: ignore
-uv: str = shutil.which("uv")  # type: ignore
+python: str = shutil.which("python")  # type: ignore
 
 
 @pytest.mark.anyio
@@ -58,25 +59,36 @@ async def test_stdio_client():
 
 
 @pytest.mark.anyio
-@pytest.mark.skipif(uv is None, reason="could not find uv command")
 async def test_stdio_client_bad_path():
     """Check that the connection doesn't hang if process errors."""
-    server_parameters = StdioServerParameters(
-        command="uv", args=["run", "non-existent-file.py"]
+    server_params = StdioServerParameters(
+        command="python", args=["-c", "non-existent-file.py"]
     )
+    async with stdio_client(server_params) as (read_stream, write_stream):
+        async with ClientSession(read_stream, write_stream) as session:
+            # The session should raise an error when the connection closes
+            with pytest.raises(McpError) as exc_info:
+                await session.initialize()
 
+            # Check that we got a connection closed error
+            assert exc_info.value.error.code == CONNECTION_CLOSED
+            assert "Connection closed" in exc_info.value.error.message
+
+
+@pytest.mark.anyio
+async def test_stdio_client_nonexistent_command():
+    """Test that stdio_client raises an error for non-existent commands."""
+    # Create a server with a non-existent command
+    server_params = StdioServerParameters(
+        command="/path/to/nonexistent/command",
+        args=["--help"],
+    )
+
+    # Should raise an error when trying to start the process
     with pytest.raises(Exception) as exc_info:
-        try:
-            with fail_after(1):
-                async with stdio_client(server_parameters) as (
-                    read_stream,
-                    _,
-                ):
-                    # Try waiting for read_stream so that we don't exit before the
-                    #  process fails.
-                    async with read_stream:
-                        async for message in read_stream:
-                            if isinstance(message, Exception):
-                                raise message
-        except TimeoutError:
-            pytest.fail("The connection hung.")
+        async with stdio_client(server_params) as (_, _):
+            pass
+
+    # The error should indicate the command was not found
+    error_message = str(exc_info.value)
+    assert "nonexistent" in error_message or "not found" in error_message.lower()