125 lines
3.9 KiB
Python
125 lines
3.9 KiB
Python
from unittest import TestCase
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from itertools import repeat
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import numpy as np
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import hashlib
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from copy import deepcopy
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from cryptarchia.cryptarchia import (
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maxvalid_bg,
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Chain,
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BlockHeader,
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Slot,
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Id,
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MockLeaderProof,
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Coin,
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Follower,
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)
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from .test_common import mk_chain, mk_config, mk_genesis_state, mk_block
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class TestForkChoice(TestCase):
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def test_fork_choice_long_sparse_chain(self):
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# The longest chain is not dense after the fork
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short_coin, long_coin = Coin(sk=0, value=100), Coin(sk=1, value=100)
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common, long_coin = mk_chain(parent=bytes(32), coin=long_coin, slots=range(50))
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long_chain_sparse_ext, long_coin = mk_chain(
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parent=common[-1].id(), coin=long_coin, slots=range(50, 100, 2)
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)
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short_chain_dense_ext, _ = mk_chain(
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parent=common[-1].id(), coin=short_coin, slots=range(50, 100)
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)
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# add more blocks to the long chain to ensure the long chain is indeed longer
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long_chain_further_ext, _ = mk_chain(
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parent=long_chain_sparse_ext[-1].id(), coin=long_coin, slots=range(100, 126)
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)
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long_chain = deepcopy(common) + long_chain_sparse_ext + long_chain_further_ext
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short_chain = deepcopy(common) + short_chain_dense_ext
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assert len(long_chain) > len(short_chain)
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# by setting a low k we trigger the density choice rule
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k = 1
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s = 50
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short_chain = Chain(short_chain, genesis=bytes(32))
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long_chain = Chain(long_chain, genesis=bytes(32))
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assert maxvalid_bg(short_chain, [long_chain], k, s) == short_chain
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# However, if we set k to the fork length, it will be accepted
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k = long_chain.length()
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assert maxvalid_bg(short_chain, [long_chain], k, s) == long_chain
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def test_fork_choice_long_dense_chain(self):
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# The longest chain is also the densest after the fork
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short_coin, long_coin = Coin(sk=0, value=100), Coin(sk=1, value=100)
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common, long_coin = mk_chain(
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parent=bytes(32), coin=long_coin, slots=range(1, 50)
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)
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long_chain_dense_ext, _ = mk_chain(
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parent=common[-1].id(), coin=long_coin, slots=range(50, 100)
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)
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short_chain_sparse_ext, _ = mk_chain(
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parent=common[-1].id(), coin=short_coin, slots=range(50, 100, 2)
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)
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long_chain = deepcopy(common) + long_chain_dense_ext
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short_chain = deepcopy(common) + short_chain_sparse_ext
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k = 1
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s = 50
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short_chain = Chain(short_chain, genesis=bytes(32))
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long_chain = Chain(long_chain, genesis=bytes(32))
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assert maxvalid_bg(short_chain, [long_chain], k, s) == long_chain
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def test_fork_choice_integration(self):
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c_a, c_b = Coin(sk=0, value=10), Coin(sk=1, value=10)
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coins = [c_a, c_b]
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config = mk_config(coins)
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genesis = mk_genesis_state(coins)
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follower = Follower(genesis, config)
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b1, c_a = mk_block(genesis.block, 1, c_a), c_a.evolve()
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follower.on_block(b1)
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assert follower.tip_id() == b1.id()
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assert follower.forks == []
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# -- then we fork --
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#
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# b2 == tip
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# /
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# b1
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# \
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# b3
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#
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b2, c_a = mk_block(b1.id(), 2, c_a), c_a.evolve()
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b3, c_b = mk_block(b1.id(), 2, c_b), c_b.evolve()
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follower.on_block(b2)
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follower.on_block(b3)
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assert follower.tip_id() == b2.id()
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assert len(follower.forks) == 1 and follower.forks[0].tip_id() == b3.id()
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# -- extend the fork causing a re-org --
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#
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# b2
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# /
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# b1
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# \
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# b3 - b4 == tip
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#
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b4, c_b = mk_block(b3.id(), 3, c_b), c_a.evolve()
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follower.on_block(b4)
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assert follower.tip_id() == b4.id()
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assert len(follower.forks) == 1 and follower.forks[0].tip_id() == b2.id()
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