def pedestal_ids_file(base_test_dir):
    """Mock pedestal ids file for testing."""
    pedestal_ids_dir = base_test_dir / "auxiliary/PedestalFinder/20200117"
    pedestal_ids_dir.mkdir(parents=True, exist_ok=True)
    file = pedestal_ids_dir / "pedestal_ids_Run01808.0000.h5"
    file.touch()
    return file