def test_is_valid_block_jumped_difficulty(last_block, block):
jumped_difficulty = 10
block.difficulty = jumped_difficulty
block.hash = f'{"0" * jumped_difficulty}111abc'
with pytest.raises(Exception,
match='The block difficulty must only adjust by 1.'):
Block.is_valid_block(last_block, block)
def is_valid_chain(chain):
"""
Validate the incoming chain.
Enforce the following rules of the blockchain:
- the chain must start with the genesis block.
- blocks must be formatted correctly.
"""
if chain[0] != Block.genesis_block():
raise Exception('The genesis block must be valid.')
for i in range(1, len(chain)):
block = chain[i]
# Previous block:
last_block = chain[i - 1]
Block.is_valid_block(last_block, block)
Blockchain.is_valid_transaction_chain(chain)
def test_is_valid_block_bad_block_hash(last_block, block):
block.hash = '000000000000000012abbbccccbc'
with pytest.raises(Exception, match='The block hash must be correct.'):
Block.is_valid_block(last_block, block)
def test_invalid_block_bad_proof_of_work(last_block, block):
block.hash = 'fff'
with pytest.raises(Exception,
match='The proof of requirement was not met.'):
Block.is_valid_block(last_block, block)
def test_is_valid_block_bad_last_hash(last_block, block):
block.last_hash = 'evil_last_hash'
with pytest.raises(Exception, match='last_hash must be correct'):
Block.is_valid_block(last_block, block)
def test_is_valid_block(last_block, block):
Block.is_valid_block(last_block, block)