Chaincode Labs Bitcoin Protocol Development Seminar Exercise

chaincode_labs_exercise.py

#!/usr/bin/env python3
"""Chaincode Exercise

Try getting node 1 to mine another block,
send it to node 2, and check that node 2 received it.
"""
from collections import defaultdict

from test_framework.blocktools import (
    create_block,
    create_coinbase,
)
from test_framework.p2p import (
    P2PInterface,
    p2p_lock,
)
from test_framework.test_framework import BitcoinTestFramework
from test_framework.util import (
    assert_equal,
)

class BaseNode(P2PInterface):
    def __init__(self):
        super().__init__()
        self.block_receive_map = defaultdict(int)

    def on_block(self, message):
        message.block.calc_sha256()
        self.block_receive_map[message.block.sha256] += 1


class ChaincodeLabsExercise(BitcoinTestFramework):
    def set_test_params(self):
        self.num_nodes = 3

    def run_test(self):
        # Setup send and receive
        node2 = self.nodes[2].add_p2p_connection(BaseNode())

        # Generate block from node 1 and send it on the network
        new_block_hash = int(self.generate(self.nodes[1], nblocks=1)[0], 16)

        """ Alternative more explicit way
        chain_tips = self.nodes[1].getchaintips()[0]
        best_block_hash = int(chain_tips['hash'], 16)
        best_block_height = chain_tips['height']
        new_block_height = best_block_height+1
        new_block = create_block(best_block_hash, create_coinbase(new_block_height))
        new_block.solve()
        new_block_hash = new_block.sha256
        self.nodes[1].submitblock(new_block.serialize().hex())
        """

        node2.wait_until(lambda: len(node2.block_receive_map) == 1)

        with p2p_lock:
            assert_equal(node2.block_receive_map[new_block_hash], 1)


if __name__ == '__main__':
    ChaincodeLabsExercise().main()