text: #!/usr/bin/env python3
  # Copyright (c) 2015-2016 The Fujicoin Core developers
  # Distributed under the MIT software license, see the accompanying
  # file COPYING or http://www.opensource.org/licenses/mit-license.php.
  
  from test_framework.test_framework import ComparisonTestFramework
  from test_framework.util import *
  from test_framework.comptool import TestManager, TestInstance, RejectResult
  from test_framework.blocktools import *
  import copy
  import time
  
  
  '''
  In this test we connect to one node over p2p, and test block requests:
  1) Valid blocks should be requested and become chain tip.
  2) Invalid block with duplicated transaction should be re-requested.
  3) Invalid block with bad coinbase value should be rejected and not
  re-requested.
  '''
  
  # Use the ComparisonTestFramework with 1 node: only use --testbinary.
  class InvalidBlockRequestTest(ComparisonTestFramework):
  
      ''' Can either run this test as 1 node with expected answers, or two and compare them. 
          Change the "outcome" variable from each TestInstance object to only do the comparison. '''
      def __init__(self):
          super().__init__()
          self.num_nodes = 1
  
      def run_test(self):
          test = TestManager(self, self.options.tmpdir)
          test.add_all_connections(self.nodes)
          self.tip = None
          self.block_time = None
          NetworkThread().start() # Start up network handling in another thread
          test.run()
  
      def get_tests(self):
          if self.tip is None:
              self.tip = int("0x" + self.nodes[0].getbestblockhash(), 0)
          self.block_time = int(time.time())+1
  
          '''
          Create a new block with an anyone-can-spend coinbase
          '''
          height = 1
          block = create_block(self.tip, create_coinbase(height), self.block_time)
          self.block_time += 1
          block.solve()
          # Save the coinbase for later
          self.block1 = block
          self.tip = block.sha256
          height += 1
          yield TestInstance([[block, True]])
  
          '''
          Now we need that block to mature so we can spend the coinbase.
          '''
          test = TestInstance(sync_every_block=False)
          for i in range(100):
              block = create_block(self.tip, create_coinbase(height), self.block_time)
              block.solve()
              self.tip = block.sha256
              self.block_time += 1
              test.blocks_and_transactions.append([block, True])
              height += 1
          yield test
  
          '''
          Now we use merkle-root malleability to generate an invalid block with
          same blockheader.
          Manufacture a block with 3 transactions (coinbase, spend of prior
          coinbase, spend of that spend).  Duplicate the 3rd transaction to 
          leave merkle root and blockheader unchanged but invalidate the block.
          '''
          block2 = create_block(self.tip, create_coinbase(height), self.block_time)
          self.block_time += 1
  
          # b'0x51' is OP_TRUE
          tx1 = create_transaction(self.block1.vtx[0], 0, b'\x51', 50 * COIN)
          tx2 = create_transaction(tx1, 0, b'\x51', 50 * COIN)
  
          block2.vtx.extend([tx1, tx2])
          block2.hashMerkleRoot = block2.calc_merkle_root()
          block2.rehash()
          block2.solve()
          orig_hash = block2.sha256
          block2_orig = copy.deepcopy(block2)
  
          # Mutate block 2
          block2.vtx.append(tx2)
          assert_equal(block2.hashMerkleRoot, block2.calc_merkle_root())
          assert_equal(orig_hash, block2.rehash())
          assert(block2_orig.vtx != block2.vtx)
  
          self.tip = block2.sha256
          yield TestInstance([[block2, RejectResult(16, b'bad-txns-duplicate')], [block2_orig, True]])
          height += 1
  
          '''
          Make sure that a totally screwed up block is not valid.
          '''
          block3 = create_block(self.tip, create_coinbase(height), self.block_time)
          self.block_time += 1
          block3.vtx[0].vout[0].nValue = 100 * COIN # Too high!
          block3.vtx[0].sha256=None
          block3.vtx[0].calc_sha256()
          block3.hashMerkleRoot = block3.calc_merkle_root()
          block3.rehash()
          block3.solve()
  
          yield TestInstance([[block3, RejectResult(16, b'bad-cb-amount')]])
  
  
  if __name__ == '__main__':
      InvalidBlockRequestTest().main()
  