nomos-specs/cryptarchia/test_fork_choice.py

77 lines
2.6 KiB
Python

from unittest import TestCase
from itertools import repeat
import numpy as np
import hashlib
from copy import deepcopy
from cryptarchia.cryptarchia import (
maxvalid_bg,
Chain,
BlockHeader,
Slot,
Id,
MockLeaderProof,
Coin,
)
from .test_common import mk_chain
class TestForkChoice(TestCase):
def test_fork_choice_long_sparse_chain(self):
# The longest chain is not dense after the fork
short_coin, long_coin = Coin(sk=0, value=100), Coin(sk=1, value=100)
common, long_coin = mk_chain(parent=bytes(32), coin=long_coin, slots=range(50))
long_chain_sparse_ext, long_coin = mk_chain(
parent=common[-1].id(), coin=long_coin, slots=range(50, 100, 2)
)
short_chain_dense_ext, _ = mk_chain(
parent=common[-1].id(), coin=short_coin, slots=range(50, 100)
)
# add more blocks to the long chain to ensure the long chain is indeed longer
long_chain_further_ext, _ = mk_chain(
parent=long_chain_sparse_ext[-1].id(), coin=long_coin, slots=range(100, 126)
)
long_chain = deepcopy(common) + long_chain_sparse_ext + long_chain_further_ext
short_chain = deepcopy(common) + short_chain_dense_ext
assert len(long_chain) > len(short_chain)
# by setting a low k we trigger the density choice rule
k = 1
s = 50
short_chain = Chain(short_chain, genesis=bytes(32))
long_chain = Chain(long_chain, genesis=bytes(32))
assert maxvalid_bg(short_chain, [long_chain], k, s) == short_chain
# However, if we set k to the fork length, it will be accepted
k = long_chain.length()
assert maxvalid_bg(short_chain, [long_chain], k, s) == long_chain
def test_fork_choice_long_dense_chain(self):
# The longest chain is also the densest after the fork
short_coin, long_coin = Coin(sk=0, value=100), Coin(sk=1, value=100)
common, long_coin = mk_chain(
parent=bytes(32), coin=long_coin, slots=range(1, 50)
)
long_chain_dense_ext, _ = mk_chain(
parent=common[-1].id(), coin=long_coin, slots=range(50, 100)
)
short_chain_sparse_ext, _ = mk_chain(
parent=common[-1].id(), coin=short_coin, slots=range(50, 100, 2)
)
long_chain = deepcopy(common) + long_chain_dense_ext
short_chain = deepcopy(common) + short_chain_sparse_ext
k = 1
s = 50
short_chain = Chain(short_chain, genesis=bytes(32))
long_chain = Chain(long_chain, genesis=bytes(32))
assert maxvalid_bg(short_chain, [long_chain], k, s) == long_chain