def test_forks(self):
node1 = TestNode()
node2 = TestNode(chain=node1.chain)
node1.all_nodes = node2.all_nodes = [node1, node2]
# create new block for node 1
new_block = blockchain.create_block(node1.chain[-1], [blockchain.add_transaction_meta({"data": "A"})])
node1.chain.append(new_block)
# create also block for node 2
# new_block = blockchain.create_block(node2.chain[-1], "B")
# node2.chain.append(new_block)
# test if chain is still valid
self.assertTrue(blockchain.verify_chain(node1.chain))
self.assertTrue(blockchain.verify_chain(node2.chain))
# test what happens if node 2 creates his own block
node2.add_transaction({"data": "B"})
node2.mine()
# now we have 2 different hashes
self.assertEqual(node1.chain[-1].previous_hash, node2.chain[-1].previous_hash)
self.assertNotEqual(node1.chain[-1].hash, node2.chain[-1].hash)
# adding transaction C and mining it in node 2 should make node 1 identical to node 2
node2.add_transaction({"data": "C"})
node2.mine()
self.assertEqual(node1.chain[-1].hash, node2.chain[-1].hash)
self.assertTrue(blockchain.verify_chain(node1.chain))
self.assertTrue(blockchain.verify_chain(node2.chain))
def test_clean_block(self):
chain = [blockchain.create_genesis_block()]
for _ in range(1):
new_block = blockchain.create_block(chain[-1], "Hello, this is a block")
chain.append(new_block)
self.assertTrue(blockchain.verify_chain(chain))
def test_dirty_block(self):
chain = [blockchain.create_genesis_block()]
for _ in range(10):
new_block = blockchain.create_block(chain[-1], "Hello, this is a block")
chain.append(new_block)
chain[3].data = "Tampered data"
self.assertFalse(blockchain.verify_chain(chain))
def test_network(self):
nodes = [TestNode()]
for _ in range(10):
nodes.append(TestNode(chain=nodes[-1].chain))
# add reference to all nodes
for n in nodes:
n.all_nodes = nodes
# add transaction
nodes[0].add_transaction({"data": "transaction#1"})
# add transaction from another node
nodes[1].add_transaction({"data": "transaction#2"})
# all nodes should have one genesis block
for n in nodes:
self.assertEqual(1, len(n.chain))
# mine
for n in nodes:
n.mine()
# after mining all the transaction should be added
self.assertEqual(2, len(nodes[0].chain))
self.assertEqual(2, len(nodes[0].chain[1].data))
# after mining the transactions should be empty
for n in nodes:
self.assertEqual(0, len(n.transactions))
# chains should be identical and valid
h = None
for n in nodes:
if h is None:
h = n.chain[-1].hash
self.assertTrue(blockchain.verify_chain(n.chain))
self.assertEqual(h, n.chain[-1].hash)
# verify transaction data
for n in nodes:
self.assertEqual(None, n.chain[0].data)
self.assertEqual("transaction#1", n.chain[1].data[0]['data'])
self.assertEqual("transaction#2", n.chain[1].data[1]['data'])
def verification():
results = bc.verify_chain()
return render_template('verification.html', results=results)