import pytest
from unittest.mock import MagicMock, patch
from m2m.nbiot import factory
from m2m.nbiot.module_bg96 import ModuleBG96

@patch('m2m.serial.serial_port.serial.Serial')
def test_factory_creates_bg96(mock_serial_cls):
    """Verify that the factory correctly instantiates a BG96 module with a mocked serial port."""
    # Setup mock to avoid hardware dependency
    mock_inst = MagicMock()
    mock_serial_cls.return_value = mock_inst
    
    module = factory('BG96', '/dev/ttyUSB0')
    
    assert isinstance(module, ModuleBG96)
    # Corrected attribute access path
    assert module.s_port._port_name == '/dev/ttyUSB0'

def test_factory_invalid_chipset():
    """Verify that an invalid chipset raises a ValueError."""
    with pytest.raises(ValueError):
        factory('INVALID_CHIPSET', '/dev/ttyUSB0')