"""The protocol and CLI must remain usable on machines without a display."""

import subprocess
import sys
import unittest


class ImportTests(unittest.TestCase):
    def test_headless_import_and_help(self):
        script = """
import sys
from controller import protocol, session, messages, discovery, cli
assert 'tkinter' not in sys.modules
assert 'bleak' not in sys.modules
try:
    cli.main(['--help'])
except SystemExit as exc:
    assert exc.code == 0
assert 'tkinter' not in sys.modules
"""
        result = subprocess.run([sys.executable, "-c", script], capture_output=True, text=True)
        self.assertEqual(result.returncode, 0, result.stderr)
        self.assertIn("--transport", result.stdout)