'When trying to add or subtract units that aren\'t compatible, throw an error'

def test_incompatible_units(self):

    q1 = u.Quantity(11.412, unit=u.meter)
    q2 = u.Quantity(21.52, unit=u.second)
    with pytest.raises(u.UnitsError):
        new_q = (q1 + q2)
