text: #!/usr/bin/env python3
  # Copyright (c) 2020 The Crown Core developers
  # Distributed under the MIT software license, see the accompanying
  # file COPYING or http://www.opensource.org/licenses/mit-license.php.
  """Test mempool descendants/ancestors information update.
  
  Test mempool update of transaction descendants/ancestors information (count, size)
  when transactions have been re-added from a disconnected block to the mempool.
  """
  import time
  
  from decimal import Decimal
  from test_framework.test_framework import CrownTestFramework
  from test_framework.util import assert_equal
  
  
  class MempoolUpdateFromBlockTest(CrownTestFramework):
      def set_test_params(self):
          self.num_nodes = 1
          self.extra_args = [['-limitdescendantsize=1000', '-limitancestorsize=1000']]
  
      def skip_test_if_missing_module(self):
          self.skip_if_no_wallet()
  
      def transaction_graph_test(self, size, n_tx_to_mine=None, start_input_txid='', end_address='', fee=Decimal(0.00100000)):
          """Create an acyclic tournament (a type of directed graph) of transactions and use it for testing.
  
          Keyword arguments:
          size -- the order N of the tournament which is equal to the number of the created transactions
          n_tx_to_mine -- the number of transaction that should be mined into a block
  
          If all of the N created transactions tx[0]..tx[N-1] reside in the mempool,
          the following holds:
              the tx[K] transaction:
              - has N-K descendants (including this one), and
              - has K+1 ancestors (including this one)
  
          More details: https://en.wikipedia.org/wiki/Tournament_(graph_theory)
          """
  
          if not start_input_txid:
              start_input_txid = self.nodes[0].getblock(self.nodes[0].getblockhash(1))['tx'][0]
  
          if not end_address:
              end_address = self.nodes[0].getnewaddress()
  
          first_block_hash = ''
          tx_id = []
          tx_size = []
          self.log.info('Creating {} transactions...'.format(size))
          for i in range(0, size):
              self.log.debug('Preparing transaction #{}...'.format(i))
              # Prepare inputs.
              if i == 0:
                  inputs = [{'txid': start_input_txid, 'vout': 0}]
                  inputs_value = self.nodes[0].gettxout(start_input_txid, 0)['value']
              else:
                  inputs = []
                  inputs_value = 0
                  for j, tx in enumerate(tx_id[0:i]):
                      # Transaction tx[K] is a child of each of previous transactions tx[0]..tx[K-1] at their output K-1.
                      vout = i - j - 1
                      inputs.append({'txid': tx_id[j], 'vout': vout})
                      inputs_value += self.nodes[0].gettxout(tx, vout)['value']
  
              self.log.debug('inputs={}'.format(inputs))
              self.log.debug('inputs_value={}'.format(inputs_value))
  
              # Prepare outputs.
              tx_count = i + 1
              if tx_count < size:
                  # Transaction tx[K] is an ancestor of each of subsequent transactions tx[K+1]..tx[N-1].
                  n_outputs = size - tx_count
                  output_value = ((inputs_value - fee) / Decimal(n_outputs)).quantize(Decimal('0.00000001'))
                  outputs = {}
                  for _ in range(n_outputs):
                      outputs[self.nodes[0].getnewaddress()] = output_value
              else:
                  output_value = (inputs_value - fee).quantize(Decimal('0.00000001'))
                  outputs = {end_address: output_value}
  
              self.log.debug('output_value={}'.format(output_value))
              self.log.debug('outputs={}'.format(outputs))
  
              # Create a new transaction.
              unsigned_raw_tx = self.nodes[0].createrawtransaction(inputs, outputs)
              signed_raw_tx = self.nodes[0].signrawtransactionwithwallet(unsigned_raw_tx)
              tx_id.append(self.nodes[0].sendrawtransaction(signed_raw_tx['hex']))
              tx_size.append(self.nodes[0].getrawmempool(True)[tx_id[-1]]['vsize'])
  
              if tx_count in n_tx_to_mine:
                  # The created transactions are mined into blocks by batches.
                  self.log.info('The batch of {} transactions has been accepted into the mempool.'.format(len(self.nodes[0].getrawmempool())))
                  block_hash = self.nodes[0].generate(1)[0]
                  if not first_block_hash:
                      first_block_hash = block_hash
                  assert_equal(len(self.nodes[0].getrawmempool()), 0)
                  self.log.info('All of the transactions from the current batch have been mined into a block.')
              elif tx_count == size:
                  # At the end all of the mined blocks are invalidated, and all of the created
                  # transactions should be re-added from disconnected blocks to the mempool.
                  self.log.info('The last batch of {} transactions has been accepted into the mempool.'.format(len(self.nodes[0].getrawmempool())))
                  start = time.time()
                  self.nodes[0].invalidateblock(first_block_hash)
                  end = time.time()
                  assert_equal(len(self.nodes[0].getrawmempool()), size)
                  self.log.info('All of the recently mined transactions have been re-added into the mempool in {} seconds.'.format(end - start))
  
          self.log.info('Checking descendants/ancestors properties of all of the in-mempool transactions...')
          for k, tx in enumerate(tx_id):
              self.log.debug('Check transaction #{}.'.format(k))
              assert_equal(self.nodes[0].getrawmempool(True)[tx]['descendantcount'], size - k)
              assert_equal(self.nodes[0].getrawmempool(True)[tx]['descendantsize'], sum(tx_size[k:size]))
              assert_equal(self.nodes[0].getrawmempool(True)[tx]['ancestorcount'], k + 1)
              assert_equal(self.nodes[0].getrawmempool(True)[tx]['ancestorsize'], sum(tx_size[0:(k + 1)]))
  
      def run_test(self):
          # Use batch size limited by DEFAULT_ANCESTOR_LIMIT = 25 to not fire "too many unconfirmed parents" error.
          self.transaction_graph_test(size=100, n_tx_to_mine=[25, 50, 75])
  
  
  if __name__ == '__main__':
      MempoolUpdateFromBlockTest().main()
  