text: #!/usr/bin/env python3
  # Copyright (c) 2019 The Ultradash developers
  # Distributed under the MIT software license, see the accompanying
  # file COPYING or http://www.opensource.org/licenses/mit-license.php.
  
  '''
  Covers the scenario of a PoS block where the coinstake input prevout is already spent.
  '''
  
  from time import sleep
  
  from fake_stake.base_test import Ultradash_FakeStakeTest
  
  class PoSFakeStake(Ultradash_FakeStakeTest):
  
      def run_test(self):
          self.description = "Covers the scenario of a PoS block where the coinstake input prevout is already spent."
          self.init_test()
  
          INITAL_MINED_BLOCKS = 150   # First mined blocks (rewards collected to spend)
          MORE_MINED_BLOCKS = 100     # Blocks mined after spending
          STAKE_AMPL_ROUNDS = 2       # Rounds of stake amplification
          self.NUM_BLOCKS = 3         # Number of spammed blocks
  
          # 1) Starting mining blocks
          self.log.info("Mining %d blocks.." % INITAL_MINED_BLOCKS)
          self.node.generate(INITAL_MINED_BLOCKS)
  
          # 2) Collect the possible prevouts
          self.log.info("Collecting all unspent coins which we generated from mining...")
  
          # 3) Create 10 addresses - Do the stake amplification
          self.log.info("Performing the stake amplification (%d rounds)..." % STAKE_AMPL_ROUNDS)
          utxo_list = self.node.listunspent()
          address_list = []
          for i in range(10):
              address_list.append(self.node.getnewaddress())
          utxo_list = self.stake_amplification(utxo_list, STAKE_AMPL_ROUNDS, address_list)
  
          self.log.info("Done. Utxo list has %d elements." % len(utxo_list))
          sleep(2)
  
          # 4) Start mining again so that spent prevouts get confirmted in a block.
          self.log.info("Mining %d more blocks..." % MORE_MINED_BLOCKS)
          self.node.generate(MORE_MINED_BLOCKS)
          sleep(2)
  
          # 5) Create "Fake Stake" blocks and send them
          self.log.info("Creating Fake stake blocks")
          err_msgs = self.test_spam("Main", utxo_list)
          if not len(err_msgs) == 0:
              self.log.error("result: " + " | ".join(err_msgs))
              raise AssertionError("TEST FAILED")
  
          self.log.info("%s PASSED" % self.__class__.__name__)
  
  if __name__ == '__main__':
      PoSFakeStake().main()
  