def test_update():
points = Points(test_util.point_gen([3, 1, 2]))
f = points.extension('tangent', start=True, end=True)
assert f(2) == 2
assert f(3) == 3
points.append((3, 2))
assert f(3) == 2
def test_update_from_empty():
points = Points([])
f = points.extension('tangent', start=True, end=True)
assert f(0) is None
points.append_list(test_util.point_gen([3, 1, 2]))
assert f(0) == 3
assert f(1) == 1
assert f(2) == 2
assert f(3) == 3