def test_blocks_ids_should_increase_one_by_one():
chain = Blockchain()
block_id_one = Block()
block_id_two = Block()
chain.add_block(block_id_one)
chain.add_block(block_id_two)
assert block_id_one.id == 1
assert block_id_two.id == 2
def test_each_block_s_previous_hash_property_should_be_previous_block_s_hash():
chain = Blockchain()
block_id_zero = Block()
block_id_one = Block()
block_id_two = Block()
chain.add_block(block_id_zero)
chain.add_block(block_id_one)
chain.add_block(block_id_two)
assert block_id_one.previous_hash == block_id_zero.hash
assert block_id_two.previous_hash == block_id_one.hash
def test_if_a_block_is_changed_then_chain_should_not_be_a_valid_chain():
chain = Blockchain()
block_id_zero = Block()
block_id_one = Block()
block_id_two = Block()
chain.add_block(block_id_zero)
chain.add_block(block_id_one)
chain.add_block(block_id_two)
block_id_one.data = {'hacked'}
block_id_one.calculate_hash()
validation = chain.validate()
assert validation == False
def test_if_the_blocks_are_not_changed_then_chain_should_be_a_valid_chain():
chain = Blockchain()
block_id_zero = Block()
block_id_one = Block()
block_id_two = Block()
chain.add_block(block_id_zero)
first_validation = chain.validate()
assert first_validation == True
chain.add_block(block_id_one)
second_validation = chain.validate()
assert second_validation == True
chain.add_block(block_id_two)
third_validation = chain.validate()
assert third_validation == True
def test_genesis_block_s_previous_block_hash_should_be_assigned_zero():
chain = Blockchain()
genesis_block = Block()
chain.add_block(genesis_block)
assert chain.blocks[0].previous_hash == 0
def test_when_genesis_block_is_added_then_genesis_block_id_should_be_assigned_zero(
):
chain = Blockchain()
genesis_block = Block()
chain.add_block(genesis_block)
assert chain.blocks[0].id == 0
