def is_transaction_chain_valid(chain):
"""
Validate chain with blocks of transactions
-- Only one reward per transaction.
-- Each transaction must only apprear once in chain.
"""
transaction_ids = []
for i in range(len(chain)):
block = chain[i]
contains_mining_reward = False
for transaction_json in block.data:
transaction_obj = Transaction.from_json(transaction_json)
if transaction_obj.id in transaction_ids:
raise Exception(
f"Transaction: {transaction_obj.id} is not unique")
transaction_ids.append(transaction_obj.id)
if transaction_obj.input == MINIING_REWARD_INPUT:
if contains_mining_reward:
raise Exception(
f'Duplicate mining reward in block: {block.hash}')
contains_mining_reward = True
else:
blockchain_tillnow = BlockChain()
blockchain_tillnow.chain = chain[0:i]
balance_tillnow = Wallet.calculate_balance(
blockchain_tillnow, transaction_obj.input["address"])
if balance_tillnow != transaction_obj.input["amount"]:
raise Exception(
f"Transaction: {transaction_obj.id} has invalid input"
)
Transaction.is_transaction_valid(transaction_obj)
def test_invalid_reward():
wallet = Wallet()
reward = Transaction.reward(wallet)
reward.output[wallet.address] = 100
with pytest.raises(Exception, match="Invalid reward transaction"):
Transaction.is_transaction_valid(reward)
def test_is_transaction_valid_with_invalid_signature():
sender_wallet = Wallet()
transaction = Transaction(sender_wallet, 'abcd', 50)
transaction.input['signature'] = Wallet().sign(transaction.output)
with pytest.raises(Exception, match="Invalid Signature"):
Transaction.is_transaction_valid(transaction)
def test_is_transaction_valid_with_invalid_outputs():
sender_wallet = Wallet()
transaction = Transaction(sender_wallet, 'abcd', 50)
transaction.output[sender_wallet.address] = 1001
with pytest.raises(
Exception,
match=
"Invalid transaction. Input amount and sum of output amounts doesnt match"
):
Transaction.is_transaction_valid(transaction)
def test_valid_reward():
reward = Transaction.reward(Wallet())
Transaction.is_transaction_valid(reward)
def test_valid_transaction():
transaction = Transaction(Wallet(), "abcd", 20)
Transaction.is_transaction_valid(transaction)
