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 blockchain using following rules
- chain must start with genesis block
- blocks must be formatted correctly
'''
if chain[0].__dict__ != Block.genesis(
).__dict__: # Python can't check equality of two objects, but dictionaries
raise Exception('The genesis block must be valid')
for i in range(1, len(chain)):
block = chain[i]
last_block = chain[i - 1]
Block.is_valid_block(last_block, block)
def test_is_valid_block_bad_block_hash(last_block, block):
block.hash = '000000000000000111abc'
with pytest.raises(Exception, match='The block hash must be correct'):
Block.is_valid_block(last_block, block)
def test_is_valid_block_bad_proof_of_work(last_block, block):
block.hash = 'fff'
with pytest.raises(Exception,
match='The proof of work requirement 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='The block last hash must be correct'
): # Tells python that we are expecting this part of code to raise an exception with given exception message
Block.is_valid_block(last_block, block)
def test_is_valid_block(last_block, block):
Block.is_valid_block(last_block, block)