nomos-specs/cryptarchia/test_ledger_state_update.py

305 lines
11 KiB
Python

from unittest import TestCase
import numpy as np
from .cryptarchia import (
Follower,
TimeConfig,
BlockHeader,
Config,
Coin,
LedgerState,
MockLeaderProof,
Slot,
Id,
)
def mk_genesis_state(initial_stake_distribution: list[Coin]) -> LedgerState:
return LedgerState(
block=bytes(32),
nonce=bytes(32),
total_stake=sum(c.value for c in initial_stake_distribution),
commitments_spend={c.commitment() for c in initial_stake_distribution},
commitments_lead={c.commitment() for c in initial_stake_distribution},
nullifiers=set(),
)
def mk_block(
parent: Id, slot: int, coin: Coin, content=bytes(32), orphaned_proofs=[]
) -> BlockHeader:
from hashlib import sha256
return BlockHeader(
slot=Slot(slot),
parent=parent,
content_size=len(content),
content_id=sha256(content).digest(),
leader_proof=MockLeaderProof.new(coin, Slot(slot), parent=parent),
orphaned_proofs=orphaned_proofs,
)
def config() -> Config:
return Config(
k=10,
active_slot_coeff=0.05,
epoch_stake_distribution_stabilization=4,
epoch_period_nonce_buffer=3,
epoch_period_nonce_stabilization=3,
time=TimeConfig(slot_duration=1, chain_start_time=0),
)
class TestLedgerStateUpdate(TestCase):
def test_ledger_state_prevents_coin_reuse(self):
leader_coin = Coin(sk=0, value=100)
genesis = mk_genesis_state([leader_coin])
follower = Follower(genesis, config())
block = mk_block(slot=0, parent=genesis.block, coin=leader_coin)
follower.on_block(block)
# Follower should have accepted the block
assert follower.local_chain.length() == 1
assert follower.local_chain.tip() == block
# Follower should have updated their ledger state to mark the leader coin as spent
assert (
follower.ledger_state[block.id()].verify_unspent(leader_coin.nullifier())
== False
)
reuse_coin_block = mk_block(slot=1, parent=block.id, coin=leader_coin)
follower.on_block(block)
# Follower should *not* have accepted the block
assert follower.local_chain.length() == 1
assert follower.local_chain.tip() == block
def test_ledger_state_is_properly_updated_on_reorg(self):
coin_1 = Coin(sk=0, value=100)
coin_2 = Coin(sk=1, value=100)
coin_3 = Coin(sk=2, value=100)
genesis = mk_genesis_state([coin_1, coin_2, coin_3])
follower = Follower(genesis, config())
# 1) coin_1 & coin_2 both concurrently win slot 0
block_1 = mk_block(parent=genesis.block, slot=0, coin=coin_1)
block_2 = mk_block(parent=genesis.block, slot=0, coin=coin_2)
# 2) follower sees block 1 first
follower.on_block(block_1)
assert follower.tip_id() == block_1.id()
assert not follower.ledger_state[block_1.id()].verify_unspent(
coin_1.nullifier()
)
# 3) then sees block 2, but sticks with block_1 as the tip
follower.on_block(block_2)
assert follower.tip_id() == block_1.id()
assert len(follower.forks) == 1, f"{len(follower.forks)}"
# 4) then coin_3 wins slot 1 and chooses to extend from block_2
block_3 = mk_block(parent=block_2.id(), slot=1, coin=coin_3)
follower.on_block(block_3)
# the follower should have switched over to the block_2 fork
assert follower.tip_id() == block_3.id()
# and the original coin_1 should now be removed from the spent pool
assert follower.ledger_state[block_3.id()].verify_unspent(coin_1.nullifier())
def test_epoch_transition(self):
leader_coins = [Coin(sk=i, value=100) for i in range(4)]
genesis = mk_genesis_state(leader_coins)
# An epoch will be 10 slots long, with stake distribution snapshot taken at the start of the epoch
# and nonce snapshot before slot 7
config = Config(
k=1,
active_slot_coeff=1,
epoch_stake_distribution_stabilization=4,
epoch_period_nonce_buffer=3,
epoch_period_nonce_stabilization=3,
time=TimeConfig(slot_duration=1, chain_start_time=0),
)
follower = Follower(genesis, config)
block_1 = mk_block(slot=0, parent=genesis.block, coin=leader_coins[0])
follower.on_block(block_1)
assert follower.tip() == block_1
assert follower.tip().slot.epoch(follower.config).epoch == 0
block_2 = mk_block(slot=9, parent=block_1.id(), coin=leader_coins[1])
follower.on_block(block_2)
assert follower.tip() == block_2
assert follower.tip().slot.epoch(follower.config).epoch == 0
block_3 = mk_block(slot=10, parent=block_2.id(), coin=leader_coins[2])
follower.on_block(block_3)
# when trying to propose a block for epoch 2, the stake distribution snapshot should be taken at the end
# of epoch 1, i.e. slot 9
# To ensure this is the case, we add a new coin just to the state associated with that slot,
# so that the new block can be accepted only if that is the snapshot used
# first, verify that if we don't change the state, the block is not accepted
block_4 = mk_block(slot=20, parent=block_3.id(), coin=Coin(sk=4, value=100))
follower.on_block(block_4)
assert follower.tip() == block_3
# then we add the coin to "spendable commitments" associated with slot 9
follower.ledger_state[block_2.id()].commitments_spend.add(
Coin(sk=4, value=100).commitment()
)
follower.on_block(block_4)
assert follower.tip() == block_4
assert follower.tip().slot.epoch(follower.config).epoch == 2
def test_evolved_coin_is_eligible_for_leadership(self):
coin = Coin(sk=0, value=100)
genesis = mk_genesis_state([coin])
config = Config(
k=1,
active_slot_coeff=1,
epoch_stake_distribution_stabilization=4,
epoch_period_nonce_buffer=3,
epoch_period_nonce_stabilization=3,
time=TimeConfig(slot_duration=1, chain_start_time=0),
)
follower = Follower(genesis, config)
# coin wins the first slot
block_1 = mk_block(slot=0, parent=genesis.block, coin=coin)
follower.on_block(block_1)
assert follower.tip_id() == block_1.id()
# coin can't be reused to win following slots:
block_2_reuse = mk_block(slot=1, parent=block_1.id(), coin=coin)
follower.on_block(block_2_reuse)
assert follower.tip_id() == block_1.id()
# but the evolved coin is eligible
block_2_evolve = mk_block(slot=1, parent=block_1.id(), coin=coin.evolve())
follower.on_block(block_2_evolve)
assert follower.tip_id() == block_2_evolve.id()
def test_new_coins_becoming_eligible_after_stake_distribution_stabilizes(self):
coin = Coin(sk=0, value=100)
genesis = mk_genesis_state([coin])
# An epoch will be 10 slots long, with stake distribution snapshot taken at the start of the epoch
# and nonce snapshot before slot 7
config = Config(
k=1,
active_slot_coeff=1,
epoch_stake_distribution_stabilization=4,
epoch_period_nonce_buffer=3,
epoch_period_nonce_stabilization=3,
time=TimeConfig(slot_duration=1, chain_start_time=0),
)
follower = Follower(genesis, config)
# ---- EPOCH 0 ----
block_0_0 = mk_block(slot=0, parent=genesis.block, coin=coin)
follower.on_block(block_0_0)
assert follower.tip() == block_0_0
# mint a new coin to be used for leader elections in upcoming epochs
coin_new = Coin(sk=1, value=10)
follower.ledger_state[block_0_0.id()].commitments_spend.add(
coin_new.commitment()
)
# the new coin is not yet eligible for elections
block_0_1_attempt = mk_block(slot=1, parent=block_0_0.id(), coin=coin_new)
follower.on_block(block_0_1_attempt)
assert follower.tip() == block_0_0
# whereas the evolved coin from genesis can be spent immediately
block_0_1 = mk_block(slot=1, parent=block_0_0.id(), coin=coin.evolve())
follower.on_block(block_0_1)
assert follower.tip() == block_0_1
# ---- EPOCH 1 ----
# The newly minted coin is still not eligible in the following epoch since the
# stake distribution snapshot is taken at the beginning of the previous epoch
block_1_0 = mk_block(slot=10, parent=block_0_1.id(), coin=coin_new)
follower.on_block(block_1_0)
assert follower.tip() == block_0_1
# ---- EPOCH 2 ----
# The coin is finally eligible 2 epochs after it was first minted
block_2_0 = mk_block(slot=20, parent=block_0_1.id(), coin=coin_new)
follower.on_block(block_2_0)
assert follower.tip() == block_2_0
# And now the minted coin can freely use the evolved coin for subsequent blocks
block_2_1 = mk_block(slot=20, parent=block_2_0.id(), coin=coin_new.evolve())
follower.on_block(block_2_1)
assert follower.tip() == block_2_1
def test_orphaned_proofs(self):
coin = Coin(sk=0, value=100)
genesis = mk_genesis_state([coin])
# An epoch will be 10 slots long, with stake distribution snapshot taken at the start of the epoch
# and nonce snapshot before slot 7
config = Config(
k=1,
active_slot_coeff=1,
epoch_stake_distribution_stabilization=4,
epoch_period_nonce_buffer=3,
epoch_period_nonce_stabilization=3,
time=TimeConfig(slot_duration=1, chain_start_time=0),
)
follower = Follower(genesis, config)
# ---- EPOCH 0 ----
block_0_0 = mk_block(slot=0, parent=genesis.block, coin=coin)
follower.on_block(block_0_0)
assert follower.tip() == block_0_0
coin_new = coin.evolve()
coin_new_new = coin_new.evolve()
block_0_1 = mk_block(slot=1, parent=block_0_0.id(), coin=coin_new_new)
follower.on_block(block_0_1)
# the coin evolved twice should not be accepted as it is not in the lead commitments
assert follower.tip() == block_0_0
# an orphaned proof with an evolved coin for the same slot as the original coin should not be accepted as the evolved coin is not in the lead commitments at slot 0
block_0_1 = mk_block(
slot=1,
parent=block_0_0.id(),
coin=coin_new_new,
orphaned_proofs=[mk_block(parent=genesis.block, slot=0, coin=coin_new)],
)
follower.on_block(block_0_1)
assert follower.tip() == block_0_0
# the coin evolved twice should be accepted as the evolved coin is in the lead commitments at slot 1 and processed before that
block_0_2 = mk_block(
slot=2,
parent=block_0_0.id(),
coin=coin_new_new,
orphaned_proofs=[mk_block(parent=block_0_0.id(), slot=1, coin=coin_new)],
)
follower.on_block(block_0_2)
assert follower.tip() == block_0_2