code: #!/usr/bin/env python3
  # Copyright (c) 2017 The Bitcoin Core developers
  # Distributed under the MIT software license, see the accompanying
  # file COPYING or http://www.opensource.org/licenses/mit-license.php.
  """Class for dashd node under test"""
  
  import decimal
  import errno
  import http.client
  import json
  import logging
  import os
  import subprocess
  import time
  
  from .authproxy import JSONRPCException
  from .mininode import NodeConn
  from .util import (
      assert_equal,
      get_rpc_proxy,
      rpc_url,
      wait_until,
      p2p_port,
  )
  
  BITCOIND_PROC_WAIT_TIMEOUT = 60
  
  class TestNode():
      """A class for representing a dashd node under test.
  
      This class contains:
  
      - state about the node (whether it's running, etc)
      - a Python subprocess.Popen object representing the running process
      - an RPC connection to the node
      - one or more P2P connections to the node
  
  
      To make things easier for the test writer, any unrecognised messages will
      be dispatched to the RPC connection."""
  
      def __init__(self, i, dirname, extra_args, rpchost, timewait, binary, stderr, mocktime, coverage_dir):
          self.index = i
          self.datadir = os.path.join(dirname, "node" + str(i))
          self.rpchost = rpchost
          if timewait:
              self.rpc_timeout = timewait
          else:
              # Wait for up to 60 seconds for the RPC server to respond
              self.rpc_timeout = 60
          if binary is None:
              self.binary = os.getenv("BITCOIND", "dashd")
          else:
              self.binary = binary
          self.stderr = stderr
          self.coverage_dir = coverage_dir
          # Most callers will just need to add extra args to the standard list below. For those callers that need more flexibity, they can just set the args property directly.
          self.extra_args = extra_args
          self.args = [self.binary, "-datadir=" + self.datadir, "-server", "-keypool=1", "-discover=0", "-rest", "-logtimemicros", "-debug", "-debugexclude=libevent", "-debugexclude=leveldb", "-mocktime=" + str(mocktime), "-uacomment=testnode%d" % i]
  
          self.cli = TestNodeCLI(os.getenv("BITCOINCLI", "dash-cli"), self.datadir)
  
          # Don't try auto backups (they fail a lot when running tests)
          self.args.append("-createwalletbackups=0")
  
          self.running = False
          self.process = None
          self.rpc_connected = False
          self.rpc = None
          self.url = None
          self.log = logging.getLogger('TestFramework.node%d' % i)
  
          self.p2ps = []
  
      def __getattr__(self, name):
          """Dispatches any unrecognised messages to the RPC connection."""
          assert self.rpc_connected and self.rpc is not None, "Error: no RPC connection"
          return getattr(self.rpc, name)
  
      def start(self, extra_args=None, stderr=None):
          """Start the node."""
          if extra_args is None:
              extra_args = self.extra_args
          if stderr is None:
              stderr = self.stderr
          self.process = subprocess.Popen(self.args + extra_args, stderr=stderr)
          self.running = True
          self.log.debug("dashd started, waiting for RPC to come up")
  
      def wait_for_rpc_connection(self):
          """Sets up an RPC connection to the dashd process. Returns False if unable to connect."""
          # Poll at a rate of four times per second
          poll_per_s = 4
          for _ in range(poll_per_s * self.rpc_timeout):
              assert self.process.poll() is None, "dashd exited with status %i during initialization" % self.process.returncode
              try:
                  self.rpc = get_rpc_proxy(rpc_url(self.datadir, self.index, self.rpchost), self.index, timeout=self.rpc_timeout, coveragedir=self.coverage_dir)
                  self.rpc.getblockcount()
                  # If the call to getblockcount() succeeds then the RPC connection is up
                  self.rpc_connected = True
                  self.url = self.rpc.url
                  self.log.debug("RPC successfully started")
                  return
              except IOError as e:
                  if e.errno != errno.ECONNREFUSED:  # Port not yet open?
                      raise  # unknown IO error
              except JSONRPCException as e:  # Initialization phase
                  # -28 RPC in warmup
                  # -342 Service unavailable, RPC server started but is shutting down due to error
                  if e.error['code'] != -28 and e.error['code'] != -342:
                      raise  # unknown JSON RPC exception
              except ValueError as e:  # cookie file not found and no rpcuser or rpcassword. dashd still starting
                  if "No RPC credentials" not in str(e):
                      raise
              time.sleep(1.0 / poll_per_s)
          raise AssertionError("Unable to connect to dashd")
  
      def get_wallet_rpc(self, wallet_name):
          assert self.rpc_connected
          assert self.rpc
          wallet_path = "wallet/%s" % wallet_name
          return self.rpc / wallet_path
  
      def stop_node(self, wait=0):
          """Stop the node."""
          if not self.running:
              return
          self.log.debug("Stopping node")
          try:
              self.stop(wait=wait)
          except http.client.CannotSendRequest:
              self.log.exception("Unable to stop node.")
          del self.p2ps[:]
  
      def is_node_stopped(self):
          """Checks whether the node has stopped.
  
          Returns True if the node has stopped. False otherwise.
          This method is responsible for freeing resources (self.process)."""
          if not self.running:
              return True
          return_code = self.process.poll()
          if return_code is None:
              return False
  
          # process has stopped. Assert that it didn't return an error code.
          assert_equal(return_code, 0)
          self.running = False
          self.process = None
          self.rpc_connected = False
          self.rpc = None
          self.log.debug("Node stopped")
          return True
  
      def wait_until_stopped(self, timeout=BITCOIND_PROC_WAIT_TIMEOUT):
          wait_until(self.is_node_stopped, timeout=timeout)
  
      def node_encrypt_wallet(self, passphrase):
          """"Encrypts the wallet.
  
          This causes dashd to shutdown, so this method takes
          care of cleaning up resources."""
          self.encryptwallet(passphrase)
          self.wait_until_stopped()
  
      def add_p2p_connection(self, p2p_conn, **kwargs):
          """Add a p2p connection to the node.
  
          This method adds the p2p connection to the self.p2ps list and also
          returns the connection to the caller."""
          if 'dstport' not in kwargs:
              kwargs['dstport'] = p2p_port(self.index)
          if 'dstaddr' not in kwargs:
              kwargs['dstaddr'] = '127.0.0.1'
          self.p2ps.append(p2p_conn)
          kwargs.update({'rpc': self.rpc, 'callback': p2p_conn})
          p2p_conn.add_connection(NodeConn(**kwargs))
  
          return p2p_conn
  
      @property
      def p2p(self):
          """Return the first p2p connection
  
          Convenience property - most tests only use a single p2p connection to each
          node, so this saves having to write node.p2ps[0] many times."""
          assert self.p2ps, "No p2p connection"
          return self.p2ps[0]
  
      def disconnect_p2ps(self):
          """Close all p2p connections to the node."""
          for p in self.p2ps:
              # Connection could have already been closed by other end.
              if p.connection is not None:
                  p.connection.disconnect_node()
          self.p2ps = []
  
  
  class TestNodeCLI():
      """Interface to bitcoin-cli for an individual node"""
  
      def __init__(self, binary, datadir):
          self.args = []
          self.binary = binary
          self.datadir = datadir
          self.input = None
  
      def __call__(self, *args, input=None):
          # TestNodeCLI is callable with bitcoin-cli command-line args
          self.args = [str(arg) for arg in args]
          self.input = input
          return self
  
      def __getattr__(self, command):
          def dispatcher(*args, **kwargs):
              return self.send_cli(command, *args, **kwargs)
          return dispatcher
  
      def send_cli(self, command, *args, **kwargs):
          """Run bitcoin-cli command. Deserializes returned string as python object."""
  
          pos_args = [str(arg) for arg in args]
          named_args = [str(key) + "=" + str(value) for (key, value) in kwargs.items()]
          assert not (pos_args and named_args), "Cannot use positional arguments and named arguments in the same bitcoin-cli call"
          p_args = [self.binary, "-datadir=" + self.datadir] + self.args
          if named_args:
              p_args += ["-named"]
          p_args += [command] + pos_args + named_args
          process = subprocess.Popen(p_args, stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE, universal_newlines=True)
          cli_stdout, cli_stderr = process.communicate(input=self.input)
          returncode = process.poll()
          if returncode:
              # Ignore cli_stdout, raise with cli_stderr
              raise subprocess.CalledProcessError(returncode, self.binary, output=cli_stderr)
          return json.loads(cli_stdout, parse_float=decimal.Decimal)
  
entities: [['DATE_TIME', '2017'], ['DATE_TIME', '.authproxy'], ['LOCATION', 'JSONRPCException'], ['PERSON', 'dirname'], ['PERSON', 'extra_args'], ['LOCATION', 'rpchost'], ['DATE_TIME', 'up to 60 seconds'], ['URL', 'logging.ge'], ['URL', 'TestFramework.no'], ['PERSON', 'extra_args'], ['URL', 'self.in'], ['URL', 'self.in'], ['URL', 'self.log.de'], ['LOCATION', 'JSONRPCException'], ['LOCATION', 'http.client'], ['LOCATION', 'p2p_conn'], ['PERSON', "kwargs['dstport"], ['LOCATION', 'self.p2ps.append(p2p_conn'], ['PERSON', 'returncode ='], ['URL', 'http://www.opensource.org/licenses/mit-license.php.'], ['IP_ADDRESS', '127.0.0.1'], ['URL', 'http.cl'], ['URL', 'self.in'], ['URL', 'os.path.jo'], ['URL', 'self.bi'], ['URL', 'os.ge'], ['URL', 'self.bi'], ['URL', 'self.st'], ['URL', 'self.co'], ['URL', 'self.ar'], ['URL', 'self.bi'], ['URL', 'self.cl'], ['URL', 'os.ge'], ['URL', 'self.ar'], ['URL', 'self.ru'], ['URL', 'self.pro'], ['URL', 'self.st'], ['URL', 'self.pro'], ['URL', 'self.ar'], ['URL', 'self.ru'], ['URL', 'self.log.de'], ['URL', 'self.pro'], ['URL', 'self.process.re'], ['URL', 'self.co'], ['URL', 'self.rpc.ge'], ['URL', 'e.er'], ['URL', 'errno.EC'], ['URL', 'e.er'], ['URL', 'e.er'], ['URL', 'time.sl'], ['URL', 'self.ru'], ['URL', 'self.log.de'], ['URL', 'self.st'], ['URL', 'http.client.Ca'], ['URL', 'self.pro'], ['URL', 'self.ru'], ['URL', 'self.pro'], ['URL', 'self.ru'], ['URL', 'self.pro'], ['URL', 'self.log.de'], ['URL', 'self.is'], ['URL', 'self.in'], ['URL', 'conn.ad'], ['URL', 'p.co'], ['URL', 'p.co'], ['URL', 'self.ar'], ['URL', 'self.bi'], ['URL', 'self.in'], ['URL', 'self.ar'], ['URL', 'self.in'], ['URL', 'self.se'], ['URL', 'kwargs.it'], ['URL', 'self.bi'], ['URL', 'self.ar'], ['URL', 'process.com'], ['URL', 'self.in'], ['URL', 'subprocess.Ca'], ['URL', 'self.bi'], ['URL', 'decimal.De']]