#!/usr/bin/env python3
"""Check the fixed wrapper using real Git in a disposable isolated repository.

Usage: python3 test_git_integration.py /path/to/fixed/git-external-diff
Do not run this test on the original buggy wrapper; use the recording-Git
unit test for the baseline to prevent recursive documentation examples.
"""
import os
from pathlib import Path
import subprocess
import sys
import tempfile

script = Path(sys.argv[1]).resolve()
with tempfile.TemporaryDirectory(prefix='pg-diff-integration-') as tmp:
    root = Path(tmp)
    env = {**os.environ, 'HOME': tmp, 'GIT_CONFIG_NOSYSTEM': '1',
           'GIT_CONFIG_GLOBAL': str(root / 'global-config')}
    def git(*args):
        return subprocess.run(['git', *args], cwd=root, env=env, check=True,
                              text=True, capture_output=True, timeout=10).stdout
    git('init', '--quiet')
    source = root / 'source file.c'
    source.write_text('old line\n')
    git('add', 'source file.c')
    git('-c', 'user.name=Test', '-c', 'user.email=test@example.invalid',
        'commit', '--quiet', '-m', 'fixture')
    config_before = (root / '.git/config').read_bytes()
    source.write_text('new line\n')
    output = git('-c', f'diff.external=/bin/bash {script}', 'diff')
    assert '*** a/source file.c\n--- b/source file.c\n' in output
    assert '! old line' in output and '! new line' in output
    assert (root / '.git/config').read_bytes() == config_before
    assert not (root / 'global-config').exists()
    print('Real Git integration: PASS (spaced filename, context diff, no config changes)')