restore stdin on error for pytest pdb

mock_stdin.py

import sys
import pytest
from io import StringIO

class MockStdin:
    def __init__(self, input_text):
        self.input_text = input_text
        self.original_stdin = None

    def __enter__(self):
        self.original_stdin = sys.stdin
        sys.stdin = StringIO(self.input_text)

    def __exit__(self, exc_type, exc_val, exc_tb):
        sys.stdin = self.original_stdin

@pytest.fixture
def mock_stdin():
    def _mock_stdin(input_text):
        return MockStdin(input_text)
    return _mock_stdin