def test_start_exit_invalid_proof_should_fail(testlang):
owner, amount = testlang.accounts[0], 100
# Create a deposit
deposit_blknum = testlang.deposit(owner, amount)
deposit_utxo_position = encode_utxo_position(deposit_blknum, 0, 0)
# Spend the deposit and submit the block
spend_utxo_position = testlang.spend_utxo(deposit_utxo_position, owner,
amount, owner)
testlang.confirm(spend_utxo_position, 0, owner)
# Start an exit
bond = testlang.root_chain.EXIT_BOND()
proof = b'' # Using empty proof
(encoded_tx, _, signatures,
confirmations) = testlang.get_exit_proof(spend_utxo_position)
with pytest.raises(TransactionFailed):
testlang.root_chain.startExit(
*decode_utxo_position(spend_utxo_position),
encoded_tx,
proof,
signatures,
confirmations,
value=bond)
def test_challenge_exit_invalid_confirmation_signatures_should_fail(testlang):
(exiting_utxo_position, spending_utxo_position) = start_exit_spend(testlang)
# Exit should fail
confirmation_signature = b'' # Using empty confirmation signatures
(encoded_tx, _) = testlang.get_challenge_proof(exiting_utxo_position, spending_utxo_position)
with pytest.raises(TransactionFailed):
testlang.root_chain.challengeExit(*decode_utxo_position(exiting_utxo_position),
encoded_tx,
confirmation_signature)
def test_challenge_exit_invalid_tx_should_fail(testlang):
(exiting_utxo_position, spending_utxo_position) = start_exit_spend(testlang)
# Exit should fail
encoded_tx = testlang.child_chain.get_transaction(exiting_utxo_position).encoded # Using the wrong tx
(_, confirmation_signature) = testlang.get_challenge_proof(exiting_utxo_position, spending_utxo_position)
with pytest.raises(TransactionFailed):
testlang.root_chain.challengeExit(*decode_utxo_position(exiting_utxo_position),
encoded_tx,
confirmation_signature)
def get_transaction(self, transaction_position):
"""Returns the transaction at a given position.
Args:
transaction_position (int): Transaction position to query.
Returns:
Transaction: Corresponding transaction object.
"""
(blknum, txindex, _) = decode_utxo_position(transaction_position)
return self.blocks[blknum].transactions[txindex]
def challenge_exit(self, exiting_utxo_position, spending_tx_position):
"""Challenges an exit with a double spend.
Args:
exiting_utxo_position (int): Position of the UTXO being exited.
spending_tx_position (int): Position of the transaction that spent the UTXO.
"""
proof_data = self.get_challenge_proof(exiting_utxo_position,
spending_tx_position)
self.root_chain.challengeExit(
*decode_utxo_position(exiting_utxo_position), *proof_data)
def start_exit(self, owner, utxo_position):
"""Starts a standard exit.
Args:
owner (EthereumAccount): Account to attempt the exit.
utxo_position (int): Position of the UTXO to be exited.
"""
bond = self.root_chain.EXIT_BOND()
self.root_chain.startExit(*decode_utxo_position(utxo_position),
*self.get_exit_proof(utxo_position),
sender=owner.key,
value=bond)
def get_challenge_proof(self, exiting_utxo_position, spending_tx_position):
"""Returns information required to submit a challenge.
Args:
exiting_utxo_position (int): Position of the UTXO being exited.
spending_tx_position (int): Position of the transaction that spent the UTXO.
Returns:
bytes, bytes: Information necessary to create a challenge proof.
"""
spend_tx = self.child_chain.get_transaction(spending_tx_position)
(_, _, oindex) = decode_utxo_position(spending_tx_position)
confirmation_signature = spend_tx.confirmations[oindex]
return (spend_tx.encoded, confirmation_signature)
def get_exit_proof(self, utxo_position):
"""Returns information required to exit
Args:
utxo_position (int): Position of the UTXO to be exited.
Returns:
bytes, bytes, bytes, bytes: Information necessary to exit the UTXO.
"""
(blknum, _, _) = decode_utxo_position(utxo_position)
block = self.child_chain.get_block(blknum)
spend_tx = self.child_chain.get_transaction(utxo_position)
encoded_tx = spend_tx.encoded
proof = block.merkle.create_membership_proof(spend_tx.encoded)
signatures = spend_tx.joined_signatures
confirmation_signatures = spend_tx.joined_confirmations
return (encoded_tx, proof, signatures, confirmation_signatures)
def test_start_exit_wrong_bond_value_should_fail(testlang):
owner, amount = testlang.accounts[0], 100
# Create a deposit
deposit_blknum = testlang.deposit(owner, amount)
deposit_utxo_position = encode_utxo_position(deposit_blknum, 0, 0)
# Spend the deposit and submit the block
spend_utxo_position = testlang.spend_utxo(deposit_utxo_position, owner,
amount, owner)
testlang.confirm(spend_utxo_position, 0, owner)
# Start an exit
bond = 0 # Using wrong bond value
with pytest.raises(TransactionFailed):
testlang.root_chain.startExit(
*decode_utxo_position(spend_utxo_position),
*testlang.get_exit_proof(spend_utxo_position),
value=bond)
def spend_utxo(self, utxo_position, new_owner, amount, signer):
"""Creates a spending transaction and inserts it into the chain.
Args:
utxo_position (int): Identifier of the UTXO to spend.
new_owner (EthereumAccount): Account to own the output of this spend.
amount (int): Amount to spend.
signer (EthereumAccount): Account to sign this transaction.
Returns:
int: Unique identifier of the spend.
"""
spend_tx = Transaction(inputs=[decode_utxo_position(utxo_position)],
outputs=[(new_owner.address, amount)])
spend_tx.sign(0, signer.key)
blknum = self.root_chain.currentPlasmaBlockNumber()
block = Block(transactions=[spend_tx], number=blknum)
self.commit_plasma_block_root(block)
return encode_utxo_position(blknum, 0, 0)
