def test_is_block_valid():
last_block = Block.genesis_block()
block = Block.mine_block(last_block, "dummy data")
Block.is_block_valid(last_block, block)
# bad last hash check
block = Block.mine_block(last_block, "dummy data")
block.last_hash = "evil_last_hash"
with pytest.raises(
Exception,
match=
"The last block hash and the last hash of the new block should match"
):
Block.is_block_valid(last_block, block)
# bad proof of work
block = Block.mine_block(last_block, "dummy data")
block.hash = "aaaaa"
with pytest.raises(Exception, match="Proof of work requirement not met"):
Block.is_block_valid(last_block, block)
# difficulty tampered
difficulty = 10
block = Block.mine_block(last_block, "dummy data")
block.difficulty = difficulty
block.hash = f"{'0' * difficulty}1111a"
with pytest.raises(Exception,
match="The block difficulty must only adjust by 1"):
Block.is_block_valid(last_block, block)
def test_genesis_block():
genesis = Block.genesis_block()
assert isinstance(genesis, Block)
for key, value in GENESIS_DATA.items():
getattr(genesis, key) == value
def test_mine_block():
last_block = Block.genesis_block()
data = "test=block"
block = Block.mine_block(last_block, data)
assert isinstance(block, Block)
assert block.data == data
assert block.last_hash == last_block.hash
assert hex_to_binary(
block.hash)[0:block.difficulty] == '0' * block.difficulty
def is_chain_valid(chain):
"""
Validate the chain
"""
if chain[0] != Block.genesis_block():
raise Exception("The genesis block is not valid")
for i in range(1, len(chain)):
block = chain[i]
last_block = chain[i - 1]
Block.is_block_valid(last_block, block)
BlockChain.is_transaction_chain_valid(chain)
def __init__(self):
self.chain = [Block.genesis_block()]
def test_slowly_mined_block():
last_block = Block.mine_block(Block.genesis_block(), 'abcd')
time.sleep(MINE_RATE / SECONDS)
mined_block = Block.mine_block(last_block, '1234')
assert mined_block.difficulty == last_block.difficulty - 1
def test_quickly_mined_block():
last_block = Block.mine_block(Block.genesis_block(), 'abcd')
mined_block = Block.mine_block(last_block, '1234')
assert mined_block.difficulty == last_block.difficulty + 1
