def test_log(): a = log(interval(1, 2)) assert a.start == 0 assert a.end == np.log(2) a = log(interval(-1, 1)) assert a.is_valid is None a = log(interval(-3, -1)) assert a.is_valid is False a = log(-3) assert a.is_valid is False a = log(2) assert a.start == np.log(2) assert a.end == np.log(2)