import pytest

from can.interfaces import virtual

@pytest.fixture(autouse=True)

def check_unclosed_virtual_channel():

"""

Pytest fixture for detecting leaked virtual CAN channels.

- The fixture yields control to the test.

- After the test completes, it acquires `virtual.channels_lock` and asserts

that `virtual.channels` is empty.

- If a test leaves behind any unclosed virtual CAN channels, the assertion

will fail, surfacing resource leaks early.

This helps maintain test isolation and prevents subtle bugs caused by

leftover state between tests.

"""

yield

with virtual.channels_lock:

assert len(virtual.channels) == 0