text: #!/usr/bin/env python3
  # Copyright (c) 2015-2016 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 nodes responses to having many blocks in flight.
  
  In this test we connect to one node over p2p, send it numerous inv's, and
  compare the resulting number of getdata requests to a max allowed value.  We
  test for exceeding 128 blocks in flight, which was the limit an 0.9 client will
  reach. [0.10 clients shouldn't request more than 16 from a single peer.]
  """
  
  from test_framework.mininode import *
  from test_framework.test_framework import BitcoinTestFramework
  from test_framework.util import *
  
  MAX_REQUESTS = 128
  
  class TestManager(NodeConnCB):
      # set up NodeConnCB callbacks, overriding base class
      def on_getdata(self, conn, message):
          self.log.debug("got getdata %s" % repr(message))
          # Log the requests
          for inv in message.inv:
              if inv.hash not in self.blockReqCounts:
                  self.blockReqCounts[inv.hash] = 0
              self.blockReqCounts[inv.hash] += 1
  
      def on_close(self, conn):
          if not self.disconnectOkay:
              raise EarlyDisconnectError(0)
  
      def __init__(self):
          NodeConnCB.__init__(self)
  
      def add_new_connection(self, connection):
          self.connection = connection
          self.blockReqCounts = {}
          self.disconnectOkay = False
  
      def run(self):
          self.connection.rpc.generate(1)  # Leave IBD
  
          numBlocksToGenerate = [8, 16, 128, 1024]
          for count in range(len(numBlocksToGenerate)):
              current_invs = []
              for i in range(numBlocksToGenerate[count]):
                  current_invs.append(CInv(2, random.randrange(0, 1 << 256)))
                  if len(current_invs) >= 50000:
                      self.connection.send_message(msg_inv(current_invs))
                      current_invs = []
              if len(current_invs) > 0:
                  self.connection.send_message(msg_inv(current_invs))
  
              # Wait and see how many blocks were requested
              time.sleep(2)
  
              total_requests = 0
              with mininode_lock:
                  for key in self.blockReqCounts:
                      total_requests += self.blockReqCounts[key]
                      if self.blockReqCounts[key] > 1:
                          raise AssertionError("Error, test failed: block %064x requested more than once" % key)
              if total_requests > MAX_REQUESTS:
                  raise AssertionError("Error, too many blocks (%d) requested" % total_requests)
              self.log.info("Round %d: success (total requests: %d)" % (count, total_requests))
  
          self.disconnectOkay = True
          self.connection.disconnect_node()
  
  
  class MaxBlocksInFlightTest(BitcoinTestFramework):
      def add_options(self, parser):
          parser.add_option("--testbinary", dest="testbinary",
                            default=os.getenv("BITCOIND", "luckybitd"),
                            help="Binary to test max block requests behavior")
  
      def __init__(self):
          super().__init__()
          self.setup_clean_chain = True
          self.num_nodes = 1
  
      def setup_network(self):
          self.nodes = start_nodes(self.num_nodes, self.options.tmpdir,
                                   extra_args=[['-whitelist=127.0.0.1']],
                                   binary=[self.options.testbinary])
  
      def run_test(self):
          test = TestManager()
          # pass log handler through to the test manager object
          test.log = self.log
          test.add_new_connection(NodeConn('127.0.0.1', p2p_port(0), self.nodes[0], test))
          NetworkThread().start()  # Start up network handling in another thread
          test.run()
  
  if __name__ == '__main__':
      MaxBlocksInFlightTest().main()
  