def test_get_fan_mode_description_pwm():
    assert _fan_mode_desc(0x02) == 'PWM'
def test_get_fan_mode_description_unknown():
    assert _fan_mode_desc(0x03) == None
    assert _fan_mode_desc(0x04) == None
    assert _fan_mode_desc(0x10) == None
    assert _fan_mode_desc(0xff) == None
def test_get_fan_mode_description_dc():
    assert _fan_mode_desc(0x01) == 'DC'
def test_get_fan_mode_description_auto():
    assert _fan_mode_desc(0x00) == None