text: #!/usr/bin/env python3
  # Copyright (c) 2014-2016 The C-Bit Core developers
  # Distributed under the MIT software license, see the accompanying
  # file COPYING or http://www.opensource.org/licenses/mit-license.php.
  
  #
  # Test -alertnotify 
  #
  
  from test_framework.test_framework import BitcoinTestFramework
  from test_framework.util import *
  
  class ForkNotifyTest(BitcoinTestFramework):
  
       def __init__(self):
          super().__init__()
          self.num_nodes = 2
          self.setup_clean_chain = False
  
  	alert_filename = None  # Set by setup_network
  
      def setup_network(self):
          self.nodes = []
          self.alert_filename = os.path.join(self.options.tmpdir, "alert.txt")
          with open(self.alert_filename, 'w', encoding='utf8') as f:
              pass  # Just open then close to create zero-length file
          self.nodes.append(start_node(0, self.options.tmpdir,
                              ["-blockversion=2", "-alertnotify=echo %s >> \"" + self.alert_filename + "\""]))
          # Node1 mines block.version=211 blocks
          self.nodes.append(start_node(1, self.options.tmpdir,
                                  ["-blockversion=211"]))
          connect_nodes(self.nodes[1], 0)
  
          self.is_network_split = False
          self.sync_all()
  
      def run_test(self):
          # Mine 51 up-version blocks
          self.nodes[1].generate(51)
          self.sync_all()
          # -alertnotify should trigger on the 51'st,
          # but mine and sync another to give
          # -alertnotify time to write
          self.nodes[1].generate(1)
          self.sync_all()
  
          with open(self.alert_filename, 'r', encoding='utf8') as f:
              alert_text = f.read()
  
          if len(alert_text) == 0:
              raise AssertionError("-alertnotify did not warn of up-version blocks")
  
          # Mine more up-version blocks, should not get more alerts:
          self.nodes[1].generate(1)
          self.sync_all()
          self.nodes[1].generate(1)
          self.sync_all()
  
          with open(self.alert_filename, 'r', encoding='utf8') as f:
              alert_text2 = f.read()
  
          if alert_text != alert_text2:
              raise AssertionError("-alertnotify excessive warning of up-version blocks")
  
  if __name__ == '__main__':
      ForkNotifyTest().main()
  