def test_validate_blockchain():
"""Test BlockChain validation"""
block = Block.genesis_block(timestamp=datetime(2000, 1, 1), difficulty=4, mining=True)
blockchain = BlockChain(block)
# Add a new candidate
assert blockchain.add_candidate(None, timestamp=datetime(2000, 1, 2))
assert blockchain.candidate_proof(4)
assert blockchain.is_valid
# Alter the index
blockchain.chain[1].index = 2
assert blockchain.chain[1].is_valid is False
assert blockchain.is_valid is False
# Mining new id
blockchain.chain[1].mining()
assert blockchain.chain[1].is_valid
assert blockchain.is_valid is False
# Change the block
blockchain.chain[1] = block
assert blockchain.is_valid is False
def test_add_candidates():
"""Validate to include a new candidate"""
block = Block.genesis_block(timestamp=datetime(2000, 1, 1), difficulty=4, mining=True)
blockchain = BlockChain(block)
assert blockchain.last_block == block
assert blockchain.candidate_block is None
assert blockchain.num_blocks == 1
assert blockchain.is_valid
# Add a new candidate
assert blockchain.add_candidate(None, timestamp=datetime(2000, 1, 2))
assert blockchain.last_block == block
assert blockchain.candidate_block is not None
assert blockchain.num_blocks == 1
assert blockchain.is_valid
# Fail in the mining process
assert blockchain.mining_candidate(maximum_iter=0) is False
# Mining the candidate block
assert blockchain.mining_candidate()
# The blockchain is now valid
assert blockchain.last_block != block
assert blockchain.candidate_block is None
assert blockchain.num_blocks == 2
assert blockchain.is_valid
def test_minimum_interval():
"""Test minimum interval period"""
block = Block.genesis_block(timestamp=datetime(2000, 1, 1, 0, 0, 0), difficulty=4, mining=True)
blockchain = BlockChain(block)
# A block in a minute
assert blockchain.add_candidate(None, timestamp=datetime(2000, 1, 1, 0, 1, 0))
assert blockchain.mining_candidate()
# A block in 30 seconds is not valid
assert blockchain.add_candidate(None, timestamp=datetime(2000, 1, 1, 0, 1, 30)) is False
def test_replace_chain():
"""Test replace a chain"""
# Generate the genesis block
block = Block.genesis_block(timestamp=datetime(2000, 1, 1), difficulty=4, mining=True)
# Generate a old chain
old_chain = BlockChain(block)
# Generate longer chain
blockchain = BlockChain(block)
# Cannot be replace the chain
assert old_chain.replace_chain(blockchain) is False
# Add new block
assert blockchain.add_candidate(None, timestamp=datetime(2000, 1, 2))
assert blockchain.candidate_proof(4)
# Replace the chain
assert old_chain.replace_chain(blockchain)
# Check the chain values
assert old_chain.num_blocks == 2
assert old_chain.candidate_block is None
def test_change_block_contains():
"""Test different attacks to the blockchain"""
data = ["Avocado", "Apple", "Cherry", "Orange", "Strawberry"]
block = Block.genesis_block(data[0], timestamp=datetime(2000, 1, 1), difficulty=4, mining=True)
blockchain = BlockChain(block)
for minute in range(1, len(data)):
assert blockchain.add_candidate(data[minute], timestamp=datetime(2000, 1, 1, 0, minute, 0))
assert blockchain.mining_candidate()
assert blockchain.is_valid
# Alter the blockchain data
blockchain.chain[2].data = 'Khaki'
assert blockchain.is_valid is False
def test_basic_blockchain():
"""Test the basic blockchain"""
# BlockChain without values
blockchain = BlockChain()
assert blockchain.last_block is not None
assert blockchain.candidate_block is None
assert blockchain.num_blocks == 1
assert blockchain.is_valid
# Manual definition of the genesis block
block = Block.genesis_block(timestamp=datetime(2000, 1, 1), difficulty=4)
blockchain = BlockChain(block)
assert blockchain.last_block is None
assert blockchain.candidate_block == block
assert blockchain.num_blocks == 0
assert blockchain.is_valid is False
# it is not possible to add a new candidate
assert blockchain.add_candidate(None) is False
# Mining the candidate block
assert blockchain.mining_candidate()
# The blockchain is now valid
assert blockchain.last_block == block
assert blockchain.candidate_block is None
assert blockchain.num_blocks == 1
assert blockchain.is_valid
def test_mining_candidate():
"""Test mining candidate """
block = Block.genesis_block(timestamp=datetime(2000, 1, 1), difficulty=4, mining=True)
blockchain = BlockChain(block)
# Add a new candidate
assert blockchain.add_candidate(None, timestamp=datetime(2000, 1, 2))
assert blockchain.mining_candidate()
# Add an empty candidate
assert blockchain.add_candidate(None)
assert blockchain.mining_candidate()
# Add an invalid candidate (same date)
assert blockchain.add_candidate(None, timestamp=datetime(2000, 1, 1)) is False
assert blockchain.mining_candidate() is False
def test_minimal_cryptocurrency():
"""Test basic process of a create a cryptocurrency"""
# Generate first user
wallet = Wallet()
# Create a new currency with 10 units
blockchain = BlockChain.new_cryptocurrency(wallet.account, 10, timestamp=datetime(2018, 1, 1, 0, 0, 0),
difficulty=4, mining=True)
# Get the wallets of Alice and Bob
alice = blockchain.get_wallet(wallet.key)
bob = blockchain.get_wallet()
assert alice.get_balance() == 10
assert bob.get_balance() == 0
# Alice transfer to Bob 5 units and get 10 units because she mining the block
assert blockchain.add_transaction(alice.key, bob.account, 5)
blockchain.generate_candidate(alice.account, timestamp=datetime(2018, 1, 1, 0, 1, 0))
blockchain.mining_candidate()
assert alice.get_balance() == 15
assert bob.get_balance() == 5
# New users Carol, Dan and Eve
carol = blockchain.get_wallet()
dan = blockchain.get_wallet()
eve = blockchain.get_wallet()
# Alice transfer 3 to Carol and 4.5 to Dan
assert blockchain.add_transaction(alice.key, carol.account, 3)
assert blockchain.add_transaction(alice.key, dan.account, 4.5)
# Bon transfer 2.2 to Dan
assert blockchain.add_transaction(bob.key, dan.account, 2.2)
# Eve mine the Block
blockchain.generate_candidate(eve.account, timestamp=datetime(2018, 1, 1, 0, 2, 0))
blockchain.mining_candidate()
assert alice.get_balance() == 7.5
assert bob.get_balance() == 2.8
assert carol.get_balance() == 3
assert dan.get_balance() == 6.7
assert eve.get_balance() == 10
def test_add_candidates_prof():
"""Test to update the proof to a candidate"""
block = Block.genesis_block(timestamp=datetime(2000, 1, 1), difficulty=4, mining=True)
blockchain = BlockChain(block)
# Add a new candidate
assert blockchain.add_candidate(None, timestamp=datetime(2000, 1, 2))
# Add proof to candidate
assert blockchain.candidate_proof(3) is False
assert blockchain.candidate_proof(4)
# Add an empty candidate
assert blockchain.add_candidate(None)
# Add an invalid candidate (same date)
assert blockchain.add_candidate(None, timestamp=datetime(2000, 1, 1)) is False
assert blockchain.candidate_proof(3) is False
assert blockchain.candidate_proof(4) is False
def test_block_repr():
"""Test the report function"""
block = Block.genesis_block(timestamp=datetime(2000, 1, 1), difficulty=4, mining=True)
blockchain = BlockChain(block)
assert repr(blockchain) == \
"Block: 0 (2000-01-01 00:00:00) - Hash: 015921ac58652b4e01d109cbb3ad10b55836e700a93e761036343ce8a82023ae\n"
for minute in range(1, 6):
blockchain.add_candidate(None, timestamp=datetime(2000, 1, 1, 0, minute, 0))
blockchain.mining_candidate()
assert repr(blockchain) == \
"Block: 5 (2000-01-01 00:05:00) - Hash: 0332726221951b73e5fb945914341aa1e92014151680375cdf8c632256dc9a54\n" + \
"Block: 4 (2000-01-01 00:04:00) - Hash: 0bf9e27631d08c326b15f7b459b47f91d9202c07ede76ce8503d636e09070402\n" + \
"Block: 3 (2000-01-01 00:03:00) - Hash: 07ded3c477dc38fe3d0bc434b2924430f81231a0d7878f906e2a655c1f17d444\n" + \
"Block: 2 (2000-01-01 00:02:00) - Hash: 0f8ed5b1cc4dca95c0c04b5b64a1ac409d636dbfd294282092f579d3872b1c15\n" + \
"Block: 1 (2000-01-01 00:01:00) - Hash: 037eeba6b1779e5edd02e4a2b4909260193adaab7ef8abaf04ddc8ab2fc39c95\n" + \
"\nand 1 block hidden"
def test_minimal_cryptocurrency():
"""Test the operation with a minimal cryptocurrency"""
wallet_1 = Wallet('aedc3975fa118bec4a1d203cd2b996c4ceb5aa398b7f7518')
# Launch a new currency
blockchain = BlockChain.new_cryptocurrency(wallet_1.public,
100,
timestamp=datetime(
2000, 1, 1, 0, 0, 0),
difficulty=4,
mining=True)
# Open the wallets
wallet_1 = blockchain.get_wallet(
'aedc3975fa118bec4a1d203cd2b996c4ceb5aa398b7f7518')
wallet_2 = blockchain.get_wallet(
'7d6433bcc63f973580dc7562d2ca79fcb12bb4e08c7e7333')
wallet_3 = blockchain.get_wallet(
'3d66f0ea52a2c5cf42893560d5522e82621790edeb7f609b')
# Ask for the accounts
assert wallet_1.get_balance() == 100
assert wallet_2.get_balance() == 0
assert wallet_3.get_balance() == 0
# Generate an unspent transaction
assert blockchain.add_transaction(wallet_1.private, wallet_2.public,
190) is False
assert blockchain.add_transaction(wallet_1.private, wallet_2.public, 90)
assert blockchain.add_transaction(wallet_1.private, wallet_2.public,
90) is False
# Generate a candidate to mining
blockchain.generate_candidate(wallet_1.public,
timestamp=datetime(2000, 1, 1, 0, 1, 0))
blockchain.mining_candidate()
# Ask for the accounts
assert wallet_1.get_balance() == 110
assert wallet_2.get_balance() == 90
assert wallet_3.get_balance() == 0
# Move more operations
assert blockchain.add_transaction(wallet_1.private, wallet_2.public, 10)
assert blockchain.add_transaction(wallet_2.private, wallet_3.public, 20)
# Generate a candidate to mining
blockchain.generate_candidate(wallet_1.public,
timestamp=datetime(2000, 1, 1, 0, 2, 0))
blockchain.mining_candidate()
# Ask for the accounts
assert wallet_1.get_balance() == 200
assert wallet_2.get_balance() == 80
assert wallet_3.get_balance() == 20
# Move more operations
assert blockchain.add_transaction(wallet_1.private, wallet_2.public, 25)
assert blockchain.add_transaction(wallet_1.private, wallet_3.public, 25)
assert blockchain.add_transaction(wallet_2.private, wallet_3.public, 50)
# Generate a candidate to mining
blockchain.generate_candidate(wallet_2.public,
timestamp=datetime(2000, 1, 1, 0, 3, 0))
blockchain.mining_candidate()
# Ask for the accounts
assert wallet_1.get_balance() == 150
assert wallet_2.get_balance() == 155
assert wallet_3.get_balance() == 95
def test_creation_blockchain():
"""Test errors during the build of an object"""
# The input is not a block object
with pytest.raises(Exception):
BlockChain(1)
def test_update_difficulty():
"""Test increase and decrease difficulty values"""
block = Block.genesis_block(timestamp=datetime(2000, 1, 1, 0, 0, 0), difficulty=4, mining=True)
blockchain = BlockChain(block)
# Change the interval for tests
blockchain.difficulty_interval = 2
# Blocks generates in a minute: the difficulty must increase
for minute in range(1, 7):
blockchain.add_candidate(None, timestamp=datetime(2000, 1, 1, 0, minute, 0))
blockchain.mining_candidate()
assert blockchain.chain[3].difficulty == 4
assert blockchain.chain[4].difficulty == 5
assert blockchain.chain[5].difficulty == 5
assert blockchain.chain[6].difficulty == 6
# Blocks generates in any eleven minutes: the difficulty must decrease
for minute in range(17, 60, 11):
blockchain.add_candidate(None, timestamp=datetime(2000, 1, 1, 0, minute, 0))
blockchain.mining_candidate()
blockchain.add_candidate(None, timestamp=datetime(2000, 1, 1, 1, 1, 0))
blockchain.mining_candidate()
assert blockchain.chain[9].difficulty == 7
assert blockchain.chain[10].difficulty == 6