eth2.0-specs/test_libs/pyspec/tests/test_finality.py

196 lines
7.5 KiB
Python

from copy import deepcopy
import pytest
import eth2spec.phase0.spec as spec
from .helpers import (
build_empty_block_for_next_slot,
fill_aggregate_attestation,
get_current_epoch,
get_epoch_start_slot,
get_valid_attestation,
next_epoch,
)
# mark entire file as 'state'
pytestmark = pytest.mark.state
def check_finality(state,
prev_state,
current_justified_changed,
previous_justified_changed,
finalized_changed):
if current_justified_changed:
assert state.current_justified_epoch > prev_state.current_justified_epoch
assert state.current_justified_root != prev_state.current_justified_root
else:
assert state.current_justified_epoch == prev_state.current_justified_epoch
assert state.current_justified_root == prev_state.current_justified_root
if previous_justified_changed:
assert state.previous_justified_epoch > prev_state.previous_justified_epoch
assert state.previous_justified_root != prev_state.previous_justified_root
else:
assert state.previous_justified_epoch == prev_state.previous_justified_epoch
assert state.previous_justified_root == prev_state.previous_justified_root
if finalized_changed:
assert state.finalized_epoch > prev_state.finalized_epoch
assert state.finalized_root != prev_state.finalized_root
else:
assert state.finalized_epoch == prev_state.finalized_epoch
assert state.finalized_root == prev_state.finalized_root
def next_epoch_with_attestations(state,
fill_cur_epoch,
fill_prev_epoch):
post_state = deepcopy(state)
blocks = []
for _ in range(spec.SLOTS_PER_EPOCH):
block = build_empty_block_for_next_slot(post_state)
if fill_cur_epoch:
slot_to_attest = post_state.slot - spec.MIN_ATTESTATION_INCLUSION_DELAY + 1
if slot_to_attest >= get_epoch_start_slot(get_current_epoch(post_state)):
cur_attestation = get_valid_attestation(post_state, slot_to_attest)
fill_aggregate_attestation(post_state, cur_attestation)
block.body.attestations.append(cur_attestation)
if fill_prev_epoch:
slot_to_attest = post_state.slot - spec.SLOTS_PER_EPOCH + 1
prev_attestation = get_valid_attestation(post_state, slot_to_attest)
fill_aggregate_attestation(post_state, prev_attestation)
block.body.attestations.append(prev_attestation)
spec.state_transition(post_state, block)
blocks.append(block)
return state, blocks, post_state
def test_finality_rule_4(state):
test_state = deepcopy(state)
blocks = []
for epoch in range(4):
prev_state, new_blocks, test_state = next_epoch_with_attestations(test_state, True, False)
blocks += new_blocks
# justification/finalization skipped at GENESIS_EPOCH
if epoch == 0:
check_finality(test_state, prev_state, False, False, False)
# justification/finalization skipped at GENESIS_EPOCH + 1
elif epoch == 1:
check_finality(test_state, prev_state, False, False, False)
elif epoch == 2:
check_finality(test_state, prev_state, True, False, False)
elif epoch >= 3:
# rule 4 of finality
check_finality(test_state, prev_state, True, True, True)
assert test_state.finalized_epoch == prev_state.current_justified_epoch
assert test_state.finalized_root == prev_state.current_justified_root
return state, blocks, test_state
def test_finality_rule_1(state):
# get past first two epochs that finality does not run on
next_epoch(state)
next_epoch(state)
pre_state = deepcopy(state)
test_state = deepcopy(state)
blocks = []
for epoch in range(3):
prev_state, new_blocks, test_state = next_epoch_with_attestations(test_state, False, True)
blocks += new_blocks
if epoch == 0:
check_finality(test_state, prev_state, True, False, False)
elif epoch == 1:
check_finality(test_state, prev_state, True, True, False)
elif epoch == 2:
# finalized by rule 1
check_finality(test_state, prev_state, True, True, True)
assert test_state.finalized_epoch == prev_state.previous_justified_epoch
assert test_state.finalized_root == prev_state.previous_justified_root
return pre_state, blocks, test_state
def test_finality_rule_2(state):
# get past first two epochs that finality does not run on
next_epoch(state)
next_epoch(state)
pre_state = deepcopy(state)
test_state = deepcopy(state)
blocks = []
for epoch in range(3):
if epoch == 0:
prev_state, new_blocks, test_state = next_epoch_with_attestations(test_state, True, False)
check_finality(test_state, prev_state, True, False, False)
elif epoch == 1:
prev_state, new_blocks, test_state = next_epoch_with_attestations(test_state, False, False)
check_finality(test_state, prev_state, False, True, False)
elif epoch == 2:
prev_state, new_blocks, test_state = next_epoch_with_attestations(test_state, False, True)
# finalized by rule 2
check_finality(test_state, prev_state, True, False, True)
assert test_state.finalized_epoch == prev_state.previous_justified_epoch
assert test_state.finalized_root == prev_state.previous_justified_root
blocks += new_blocks
return pre_state, blocks, test_state
def test_finality_rule_3(state):
"""
Test scenario described here
https://github.com/ethereum/eth2.0-specs/issues/611#issuecomment-463612892
"""
# get past first two epochs that finality does not run on
next_epoch(state)
next_epoch(state)
pre_state = deepcopy(state)
test_state = deepcopy(state)
blocks = []
prev_state, new_blocks, test_state = next_epoch_with_attestations(test_state, True, False)
blocks += new_blocks
check_finality(test_state, prev_state, True, False, False)
# In epoch N, JE is set to N, prev JE is set to N-1
prev_state, new_blocks, test_state = next_epoch_with_attestations(test_state, True, False)
blocks += new_blocks
check_finality(test_state, prev_state, True, True, True)
# In epoch N+1, JE is N, prev JE is N-1, and not enough messages get in to do anything
prev_state, new_blocks, test_state = next_epoch_with_attestations(test_state, False, False)
blocks += new_blocks
check_finality(test_state, prev_state, False, True, False)
# In epoch N+2, JE is N, prev JE is N, and enough messages from the previous epoch get in to justify N+1.
# N+1 now becomes the JE. Not enough messages from epoch N+2 itself get in to justify N+2
prev_state, new_blocks, test_state = next_epoch_with_attestations(test_state, False, True)
blocks += new_blocks
# rule 2
check_finality(test_state, prev_state, True, False, True)
# In epoch N+3, LJE is N+1, prev LJE is N, and enough messages get in to justify epochs N+2 and N+3.
prev_state, new_blocks, test_state = next_epoch_with_attestations(test_state, True, True)
blocks += new_blocks
# rule 3
check_finality(test_state, prev_state, True, True, True)
assert test_state.finalized_epoch == prev_state.current_justified_epoch
assert test_state.finalized_root == prev_state.current_justified_root
return pre_state, blocks, test_state