text: #!/usr/bin/env python3
  # Copyright (c) 2014-2016 The Bitcoin Core developers
  # Distributed under the MIT software license, see the accompanying
  # file COPYING or http://www.opensource.org/licenses/mit-license.php.
  
  #
  # Test InvalidateBlock code
  #
  
  from test_framework.test_framework import BitcoinTestFramework
  from test_framework.util import *
  
  class InvalidateTest(BitcoinTestFramework):
      
          
      def __init__(self):
          super().__init__()
          self.setup_clean_chain = True
          self.num_nodes = 3
  
      def setup_network(self):
          self.nodes = []
          self.is_network_split = False 
          self.nodes.append(start_node(0, self.options.tmpdir, ["-debug"]))
          self.nodes.append(start_node(1, self.options.tmpdir, ["-debug"]))
          self.nodes.append(start_node(2, self.options.tmpdir, ["-debug"]))
          
      def run_test(self):
          print("Make sure we repopulate setBlockIndexCandidates after InvalidateBlock:")
          print("Mine 4 blocks on Node 0")
          self.nodes[0].generate(4)
          assert(self.nodes[0].getblockcount() == 4)
          besthash = self.nodes[0].getbestblockhash()
  
          print("Mine competing 6 blocks on Node 1")
          self.nodes[1].generate(6)
          assert(self.nodes[1].getblockcount() == 6)
  
          print("Connect nodes to force a reorg")
          connect_nodes_bi(self.nodes,0,1)
  
          sync_blocks(self.nodes[0:2])
          assert(self.nodes[0].getblockcount() == 6)
          badhash = self.nodes[1].getblockhash(2)
  
          print("Invalidate block 2 on node 0 and verify we reorg to node 0's original chain")
          self.nodes[0].invalidateblock(badhash)
          newheight = self.nodes[0].getblockcount()
          newhash = self.nodes[0].getbestblockhash()
          if (newheight != 4 or newhash != besthash):
              raise AssertionError("Wrong tip for node0, hash %s, height %d"%(newhash,newheight))
  
          print("\nMake sure we won't reorg to a lower work chain:")
          connect_nodes_bi(self.nodes,1,2)
          print("Sync node 2 to node 1 so both have 6 blocks")
          sync_blocks(self.nodes[1:3])
          assert(self.nodes[2].getblockcount() == 6)
          print("Invalidate block 5 on node 1 so its tip is now at 4")
          self.nodes[1].invalidateblock(self.nodes[1].getblockhash(5))
          assert(self.nodes[1].getblockcount() == 4)
          print("Invalidate block 3 on node 2, so its tip is now 2")
          self.nodes[2].invalidateblock(self.nodes[2].getblockhash(3))
          assert(self.nodes[2].getblockcount() == 2)
          print("..and then mine a block")
          self.nodes[2].generate(1)
          print("Verify all nodes are at the right height")
          time.sleep(5)
          for i in range(3):
              print(i,self.nodes[i].getblockcount())
          assert(self.nodes[2].getblockcount() == 3)
          assert(self.nodes[0].getblockcount() == 4)
          node1height = self.nodes[1].getblockcount()
          if node1height < 4:
              raise AssertionError("Node 1 reorged to a lower height: %d"%node1height)
  
  if __name__ == '__main__':
      InvalidateTest().main()
  