def test_derive(self):
landing_gross_weight = LandingGrossWeight()
landing_gross_weight.set_flight_attr = Mock()
touchdown_gross_weight = KPV('Gross Weight At Touchdown',
items=[KeyPointValue(5, 15, 'a'),
KeyPointValue(12, 120, 'b')])
landing_gross_weight.derive(touchdown_gross_weight)
landing_gross_weight.set_flight_attr.assert_called_once_with(120)
def test_can_operate(self):
self.assertEqual(LandingGrossWeight.get_operational_combinations(),
[('Gross Weight At Touchdown',)])
