diff --git a/test/functional/abc-invalid-message.py b/test/functional/abc-invalid-message.py
index f1a40b109..b27023dfd 100755
--- a/test/functional/abc-invalid-message.py
+++ b/test/functional/abc-invalid-message.py
@@ -1,103 +1,102 @@
 #!/usr/bin/env python3
 # Copyright (c) 2019 The Bitcoin developers
 # Distributed under the MIT software license, see the accompanying
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 """ABC Invalid Message Test
 
 Test that invalid messages get rejected and/or ban the sender as expected for
 each case.
 """
 
 import struct
 
 from test_framework.messages import NODE_NETWORK, msg_version
 from test_framework.mininode import (
-    MAGIC_BYTES,
     mininode_lock,
     msg_ping,
     P2PInterface,
 )
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import wait_until
 
 
 def msg_bad_checksum(connection, original_message):
     message_data = bytearray(connection.build_message(original_message))
 
     data = original_message.serialize()
     i = 0
-    i += len(MAGIC_BYTES[connection.network])
+    i += len(connection.magic_bytes)
     i += 12
     i += len(struct.pack("<I", len(data)))
 
     # Make the checksum invalid
     message_data[i] = message_data[i] ^ 0xAA
     return message_data
 
 
 class BadVersionP2PInterface(P2PInterface):
     def peer_connect(self, *args, services=NODE_NETWORK,
                      send_version=False, **kwargs):
         create_conn = super().peer_connect(*args, send_version=send_version, **kwargs)
 
         # Send version message with invalid checksum
         vt = msg_version()
         vt.nServices = services
         vt.addrTo.ip = self.dstaddr
         vt.addrTo.port = self.dstport
         vt.addrFrom.ip = "0.0.0.0"
         vt.addrFrom.port = 0
         invalid_vt = msg_bad_checksum(self, vt)
         # Will be sent right after connection_made
         self.on_connection_send_msg = invalid_vt
         self.on_connection_send_msg_is_raw = True
 
         return create_conn
 
 
 class InvalidMessageTest(BitcoinTestFramework):
     def set_test_params(self):
         self.setup_clean_chain = False
         self.num_nodes = 2
 
     def run_test(self):
         # Try to connect to a node using an invalid checksum on version message
         bad_interface = BadVersionP2PInterface()
         self.nodes[0].add_p2p_connection(
             bad_interface, send_version=False, wait_for_verack=False)
 
         # Also connect to a node with a valid version message
         interface = P2PInterface()
         # Node with valid version message should connect successfully
         connection = self.nodes[1].add_p2p_connection(interface)
 
         # The invalid version message should cause a disconnect on the first
         # connection because we are now banned
         bad_interface.wait_for_disconnect()
 
         # Create a valid message
         valid_message = msg_ping(interface.ping_counter)
 
         def wait_for_ping():
             def check_ping():
                 if not interface.last_message.get("pong"):
                     return False
                 return interface.last_message["pong"].nonce == interface.ping_counter
             wait_until(check_ping, lock=mininode_lock)
             interface.ping_counter += 1
 
         # The valid message is accepted
         connection.send_message(valid_message)
         wait_for_ping()
 
         # Make an invalid copy of the valid message with an invalid checksum
         invalid_message = msg_bad_checksum(connection, valid_message)
 
         # The invalid message should cause a disconnect because we are now
         # banned
         connection.send_raw_message(invalid_message)
         interface.wait_for_disconnect()
 
 
 if __name__ == '__main__':
     InvalidMessageTest().main()
diff --git a/test/functional/p2p_invalid_messages.py b/test/functional/p2p_invalid_messages.py
index 73e54d17d..b0cdfda96 100755
--- a/test/functional/p2p_invalid_messages.py
+++ b/test/functional/p2p_invalid_messages.py
@@ -1,178 +1,222 @@
 #!/usr/bin/env python3
 # Copyright (c) 2015-2018 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 node responses to invalid network messages."""
 import struct
 
 from test_framework import messages
 from test_framework.mininode import P2PDataStore
 from test_framework.test_framework import BitcoinTestFramework
 
 
 class msg_unrecognized:
     """Nonsensical message. Modeled after similar types in test_framework.messages."""
 
     command = b'badmsg'
 
-    def __init__(self, str_data):
+    def __init__(self, *, str_data):
         self.str_data = str_data.encode() if not isinstance(str_data, bytes) else str_data
 
     def serialize(self):
         return messages.ser_string(self.str_data)
 
     def __repr__(self):
         return "{}(data={})".format(self.command, self.str_data)
 
 
-class msg_nametoolong(msg_unrecognized):
-
-    command = b'thisnameiswayyyyyyyyytoolong'
-
-
 class InvalidMessagesTest(BitcoinTestFramework):
-
     def set_test_params(self):
         self.num_nodes = 1
         self.setup_clean_chain = True
 
     def run_test(self):
         """
+         . Test msg header
         0. Send a bunch of large (2MB) messages of an unrecognized type. Check to see
            that it isn't an effective DoS against the node.
 
         1. Send an oversized (2MB+) message and check that we're disconnected.
 
         2. Send a few messages with an incorrect data size in the header, ensure the
            messages are ignored.
-
-        3. Send an unrecognized message with a command name longer than 12 characters.
-
         """
+        self.test_magic_bytes()
+        self.test_checksum()
+        self.test_size()
+        self.test_command()
+
         node = self.nodes[0]
         self.node = node
         node.add_p2p_connection(P2PDataStore())
         conn2 = node.add_p2p_connection(P2PDataStore())
 
         # 2MB, per MAX_PROTOCOL_MESSAGE_LENGTH
         msg_limit = 2 * 1024 * 1024
         # Account for the 4-byte length prefix
         valid_data_limit = msg_limit - 5
 
         #
         # 0.
         #
         # Send as large a message as is valid, ensure we aren't disconnected but
         # also can't exhaust resources.
         #
-        msg_at_size = msg_unrecognized("b" * valid_data_limit)
+        msg_at_size = msg_unrecognized(str_data="b" * valid_data_limit)
         assert len(msg_at_size.serialize()) == msg_limit
 
         self.log.info(
             "Sending a bunch of large, junk messages to test memory exhaustion. May take a bit...")
 
         # Run a bunch of times to test for memory exhaustion.
         for _ in range(80):
             node.p2p.send_message(msg_at_size)
 
         # Check that, even though the node is being hammered by nonsense from one
         # connection, it can still service other peers in a timely way.
         for _ in range(20):
             conn2.sync_with_ping(timeout=2)
 
         # Peer 1, despite serving up a bunch of nonsense, should still be
         # connected.
         self.log.info("Waiting for node to drop junk messages.")
         node.p2p.sync_with_ping(timeout=320)
         assert node.p2p.is_connected
 
         #
         # 1.
         #
         # Send an oversized message, ensure we're disconnected.
         #
-        msg_over_size = msg_unrecognized("b" * (valid_data_limit + 1))
+        msg_over_size = msg_unrecognized(str_data="b" * (valid_data_limit + 1))
         assert len(msg_over_size.serialize()) == (msg_limit + 1)
 
         with node.assert_debug_log(["Oversized header detected"]):
             # An unknown message type (or *any* message type) over
             # MAX_PROTOCOL_MESSAGE_LENGTH should result in a disconnect.
             node.p2p.send_message(msg_over_size)
             node.p2p.wait_for_disconnect(timeout=4)
 
         node.disconnect_p2ps()
         conn = node.add_p2p_connection(P2PDataStore())
         conn.wait_for_verack()
 
         #
         # 2.
         #
         # Send messages with an incorrect data size in the header.
         #
         actual_size = 100
-        msg = msg_unrecognized("b" * actual_size)
+        msg = msg_unrecognized(str_data="b" * actual_size)
 
         # TODO: handle larger-than cases. I haven't been able to pin down what
         # behavior to expect.
         for wrong_size in (2, 77, 78, 79):
             self.log.info(
                 "Sending a message with incorrect size of {}".format(wrong_size))
 
             # Unmodified message should submit okay.
             node.p2p.send_and_ping(msg)
 
             # A message lying about its data size results in a disconnect when the incorrect
             # data size is less than the actual size.
             #
             # TODO: why does behavior change at 78 bytes?
             #
             node.p2p.send_raw_message(
                 self._tweak_msg_data_size(
                     msg, wrong_size))
 
             # For some reason unknown to me, we sometimes have to push additional data to the
             # peer in order for it to realize a disconnect.
             try:
                 node.p2p.send_message(messages.msg_ping(nonce=123123))
             except IOError:
                 pass
 
             node.p2p.wait_for_disconnect(timeout=10)
             node.disconnect_p2ps()
             node.add_p2p_connection(P2PDataStore())
 
-        #
-        # 3.
-        #
-        # Send a message with a too-long command name.
-        #
-        node.p2p.send_message(msg_nametoolong("foobar"))
-        node.p2p.wait_for_disconnect(timeout=4)
-
         # Node is still up.
         conn = node.add_p2p_connection(P2PDataStore())
         conn.sync_with_ping()
 
+    def test_magic_bytes(self):
+        conn = self.nodes[0].add_p2p_connection(P2PDataStore())
+        conn.magic_bytes = b'\x00\x11\x22\x32'
+        with self.nodes[0].assert_debug_log(['PROCESSMESSAGE: INVALID MESSAGESTART ping']):
+            conn.send_message(messages.msg_ping(nonce=0xff))
+            conn.wait_for_disconnect(timeout=1)
+            self.nodes[0].disconnect_p2ps()
+
+    def test_checksum(self):
+        conn = self.nodes[0].add_p2p_connection(P2PDataStore())
+        with self.nodes[0].assert_debug_log(['ProcessMessages(badmsg, 2 bytes): CHECKSUM ERROR expected 78df0a04 was ffffffff']):
+            msg = conn.build_message(msg_unrecognized(str_data="d"))
+            cut_len = (
+                # magic
+                4 +
+                # command
+                12 +
+                # len
+                4
+            )
+            # modify checksum
+            msg = msg[:cut_len] + b'\xff' * 4 + msg[cut_len + 4:]
+            self.nodes[0].p2p.send_raw_message(msg)
+            conn.wait_for_disconnect()
+            self.nodes[0].disconnect_p2ps()
+
+    def test_size(self):
+        conn = self.nodes[0].add_p2p_connection(P2PDataStore())
+        with self.nodes[0].assert_debug_log(['']):
+            msg = conn.build_message(msg_unrecognized(str_data="d"))
+            cut_len = (
+                # magic
+                4 +
+                # command
+                12
+            )
+            # modify len to MAX_SIZE + 1
+            msg = msg[:cut_len] + \
+                struct.pack("<I", 0x02000000 + 1) + msg[cut_len + 4:]
+            self.nodes[0].p2p.send_raw_message(msg)
+            conn.wait_for_disconnect(timeout=1)
+            self.nodes[0].disconnect_p2ps()
+
+    def test_command(self):
+        conn = self.nodes[0].add_p2p_connection(P2PDataStore())
+        with self.nodes[0].assert_debug_log(['PROCESSMESSAGE: ERRORS IN HEADER']):
+            msg = msg_unrecognized(str_data="d")
+            msg.command = b'\xff' * 12
+            msg = conn.build_message(msg)
+            # Modify command
+            msg = msg[:7] + b'\x00' + msg[7 + 1:]
+            self.nodes[0].p2p.send_raw_message(msg)
+            conn.sync_with_ping(timeout=1)
+            self.nodes[0].disconnect_p2ps()
+
     def _tweak_msg_data_size(self, message, wrong_size):
         """
         Return a raw message based on another message but with an incorrect data size in
         the message header.
         """
         raw_msg = self.node.p2p.build_message(message)
 
         bad_size_bytes = struct.pack("<I", wrong_size)
         num_header_bytes_before_size = 4 + 12
 
         # Replace the correct data size in the message with an incorrect one.
         raw_msg_with_wrong_size = (
             raw_msg[:num_header_bytes_before_size] +
             bad_size_bytes +
             raw_msg[(num_header_bytes_before_size + len(bad_size_bytes)):]
         )
         assert len(raw_msg) == len(raw_msg_with_wrong_size)
 
         return raw_msg_with_wrong_size
 
 
 if __name__ == '__main__':
     InvalidMessagesTest().main()
diff --git a/test/functional/test_framework/mininode.py b/test/functional/test_framework/mininode.py
index ffe74bb0c..95d66d655 100755
--- a/test/functional/test_framework/mininode.py
+++ b/test/functional/test_framework/mininode.py
@@ -1,663 +1,663 @@
 #!/usr/bin/env python3
 # Copyright (c) 2010 ArtForz -- public domain half-a-node
 # Copyright (c) 2012 Jeff Garzik
 # Copyright (c) 2010-2019 The Bitcoin Core developers
 # Distributed under the MIT software license, see the accompanying
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 """Bitcoin P2P network half-a-node.
 
 This python code was modified from ArtForz' public domain half-a-node, as
 found in the mini-node branch of http://github.com/jgarzik/pynode.
 
 P2PConnection: A low-level connection object to a node's P2P interface
 P2PInterface: A high-level interface object for communicating to a node over P2P
 P2PDataStore: A p2p interface class that keeps a store of transactions and blocks
               and can respond correctly to getdata and getheaders messages"""
 import asyncio
 from collections import defaultdict
 from io import BytesIO
 import logging
 import struct
 import sys
 import threading
 
 from test_framework.messages import (
     CBlockHeader,
     MIN_VERSION_SUPPORTED,
     msg_addr,
     msg_avapoll,
     msg_tcpavaresponse,
     msg_block,
     MSG_BLOCK,
     msg_blocktxn,
     msg_cmpctblock,
     msg_feefilter,
     msg_getaddr,
     msg_getblocks,
     msg_getblocktxn,
     msg_getdata,
     msg_getheaders,
     msg_headers,
     msg_inv,
     msg_mempool,
     msg_notfound,
     msg_ping,
     msg_pong,
     msg_reject,
     msg_sendcmpct,
     msg_sendheaders,
     msg_tx,
     MSG_TX,
     MSG_TYPE_MASK,
     msg_verack,
     msg_version,
     NODE_NETWORK,
     sha256,
 )
 from test_framework.util import wait_until
 
 logger = logging.getLogger("TestFramework.mininode")
 
 MESSAGEMAP = {
     b"addr": msg_addr,
     b"avapoll": msg_avapoll,
     b"avaresponse": msg_tcpavaresponse,
     b"block": msg_block,
     b"blocktxn": msg_blocktxn,
     b"cmpctblock": msg_cmpctblock,
     b"feefilter": msg_feefilter,
     b"getaddr": msg_getaddr,
     b"getblocks": msg_getblocks,
     b"getblocktxn": msg_getblocktxn,
     b"getdata": msg_getdata,
     b"getheaders": msg_getheaders,
     b"headers": msg_headers,
     b"inv": msg_inv,
     b"mempool": msg_mempool,
     b"notfound": msg_notfound,
     b"ping": msg_ping,
     b"pong": msg_pong,
     b"reject": msg_reject,
     b"sendcmpct": msg_sendcmpct,
     b"sendheaders": msg_sendheaders,
     b"tx": msg_tx,
     b"verack": msg_verack,
     b"version": msg_version,
 }
 
 MAGIC_BYTES = {
     "mainnet": b"\xe3\xe1\xf3\xe8",
     "testnet3": b"\xf4\xe5\xf3\xf4",
     "regtest": b"\xda\xb5\xbf\xfa",
 }
 
 
 class P2PConnection(asyncio.Protocol):
     """A low-level connection object to a node's P2P interface.
 
     This class is responsible for:
 
     - opening and closing the TCP connection to the node
     - reading bytes from and writing bytes to the socket
     - deserializing and serializing the P2P message header
     - logging messages as they are sent and received
 
     This class contains no logic for handing the P2P message payloads. It must be
     sub-classed and the on_message() callback overridden."""
 
     def __init__(self):
         # The underlying transport of the connection.
         # Should only call methods on this from the NetworkThread, c.f.
         # call_soon_threadsafe
         self._transport = None
 
     @property
     def is_connected(self):
         return self._transport is not None
 
     def peer_connect(self, dstaddr, dstport, net="regtest"):
         assert not self.is_connected
         self.dstaddr = dstaddr
         self.dstport = dstport
         # The initial message to send after the connection was made:
         self.on_connection_send_msg = None
         self.on_connection_send_msg_is_raw = False
         self.recvbuf = b""
-        self.network = net
+        self.magic_bytes = MAGIC_BYTES[net]
         logger.debug('Connecting to Bitcoin Node: {}:{}'.format(
             self.dstaddr, self.dstport))
 
         loop = NetworkThread.network_event_loop
         conn_gen_unsafe = loop.create_connection(
             lambda: self, host=self.dstaddr, port=self.dstport)
 
         def conn_gen(): return loop.call_soon_threadsafe(
             loop.create_task, conn_gen_unsafe)
         return conn_gen
 
     def peer_disconnect(self):
         # Connection could have already been closed by other end.
         NetworkThread.network_event_loop.call_soon_threadsafe(
             lambda: self._transport and self._transport.abort())
 
     # Connection and disconnection methods
 
     def connection_made(self, transport):
         """asyncio callback when a connection is opened."""
         assert not self._transport
         logger.debug("Connected & Listening: {}:{}".format(
             self.dstaddr, self.dstport))
         self._transport = transport
         if self.on_connection_send_msg:
             if self.on_connection_send_msg_is_raw:
                 self.send_raw_message(self.on_connection_send_msg)
             else:
                 self.send_message(self.on_connection_send_msg)
             # Never used again
             self.on_connection_send_msg = None
         self.on_open()
 
     def connection_lost(self, exc):
         """asyncio callback when a connection is closed."""
         if exc:
             logger.warning("Connection lost to {}:{} due to {}".format(
                 self.dstaddr, self.dstport, exc))
         else:
             logger.debug("Closed connection to: {}:{}".format(
                 self.dstaddr, self.dstport))
         self._transport = None
         self.recvbuf = b""
         self.on_close()
 
     # Socket read methods
 
     def data_received(self, t):
         """asyncio callback when data is read from the socket."""
         with mininode_lock:
             if len(t) > 0:
                 self.recvbuf += t
 
         while True:
             msg = self._on_data()
             if msg is None:
                 break
             self.on_message(msg)
 
     def _on_data(self):
         """Try to read P2P messages from the recv buffer.
 
         This method reads data from the buffer in a loop. It deserializes,
         parses and verifies the P2P header, then passes the P2P payload to
         the on_message callback for processing."""
         try:
             with mininode_lock:
                 if len(self.recvbuf) < 4:
                     return None
-                if self.recvbuf[:4] != MAGIC_BYTES[self.network]:
+                if self.recvbuf[:4] != self.magic_bytes:
                     raise ValueError(
                         "got garbage {}".format(repr(self.recvbuf)))
                 if len(self.recvbuf) < 4 + 12 + 4 + 4:
                     return None
                 command = self.recvbuf[4:4 + 12].split(b"\x00", 1)[0]
                 msglen = struct.unpack(
                     "<i", self.recvbuf[4 + 12:4 + 12 + 4])[0]
                 checksum = self.recvbuf[4 + 12 + 4:4 + 12 + 4 + 4]
                 if len(self.recvbuf) < 4 + 12 + 4 + 4 + msglen:
                     return None
                 msg = self.recvbuf[4 + 12 + 4 + 4:4 + 12 + 4 + 4 + msglen]
                 h = sha256(sha256(msg))
                 if checksum != h[:4]:
                     raise ValueError("got bad checksum " + repr(self.recvbuf))
                 self.recvbuf = self.recvbuf[4 + 12 + 4 + 4 + msglen:]
                 if command not in MESSAGEMAP:
                     raise ValueError("Received unknown command from {}:{}: '{}' {}".format(
                         self.dstaddr, self.dstport, command, repr(msg)))
                 f = BytesIO(msg)
                 m = MESSAGEMAP[command]()
                 m.deserialize(f)
                 self._log_message("receive", m)
                 return m
         except Exception as e:
             logger.exception('Error reading message:', repr(e))
             raise
 
     def on_message(self, message):
         """Callback for processing a P2P payload. Must be overridden by derived class."""
         raise NotImplementedError
 
     # Socket write methods
 
     def send_message(self, message):
         """Send a P2P message over the socket.
 
         This method takes a P2P payload, builds the P2P header and adds
         the message to the send buffer to be sent over the socket."""
         if not self.is_connected:
             raise IOError('Not connected')
         tmsg = self.build_message(message)
         self._log_message("send", message)
         return self.send_raw_message(tmsg)
 
     def send_raw_message(self, raw_message_bytes):
         """Send any raw message over the socket.
 
         This method adds a raw message to the send buffer to be sent over the
         socket."""
         if not self.is_connected:
             raise IOError('Not connected')
 
         def maybe_write():
             if not self._transport:
                 return
             if self._transport.is_closing():
                 return
             self._transport.write(raw_message_bytes)
         NetworkThread.network_event_loop.call_soon_threadsafe(maybe_write)
 
     # Class utility methods
 
     def build_message(self, message):
         """Build a serialized P2P message"""
         command = message.command
         data = message.serialize()
-        tmsg = MAGIC_BYTES[self.network]
+        tmsg = self.magic_bytes
         tmsg += command
         tmsg += b"\x00" * (12 - len(command))
         tmsg += struct.pack("<I", len(data))
         th = sha256(data)
         h = sha256(th)
         tmsg += h[:4]
         tmsg += data
         return tmsg
 
     def _log_message(self, direction, msg):
         """Logs a message being sent or received over the connection."""
         if direction == "send":
             log_message = "Send message to "
         elif direction == "receive":
             log_message = "Received message from "
         log_message += "{}:{}: {}".format(
             self.dstaddr, self.dstport, repr(msg)[:500])
         if len(log_message) > 500:
             log_message += "... (msg truncated)"
         logger.debug(log_message)
 
 
 class P2PInterface(P2PConnection):
     """A high-level P2P interface class for communicating with a Bitcoin Cash node.
 
     This class provides high-level callbacks for processing P2P message
     payloads, as well as convenience methods for interacting with the
     node over P2P.
 
     Individual testcases should subclass this and override the on_* methods
     if they want to alter message handling behaviour."""
 
     def __init__(self):
         super().__init__()
 
         # Track number of messages of each type received and the most recent
         # message of each type
         self.message_count = defaultdict(int)
         self.last_message = {}
 
         # A count of the number of ping messages we've sent to the node
         self.ping_counter = 1
 
         # The network services received from the peer
         self.nServices = 0
 
     def peer_connect(self, *args, services=NODE_NETWORK,
                      send_version=True, **kwargs):
         create_conn = super().peer_connect(*args, **kwargs)
 
         if send_version:
             # Send a version msg
             vt = msg_version()
             vt.nServices = services
             vt.addrTo.ip = self.dstaddr
             vt.addrTo.port = self.dstport
             vt.addrFrom.ip = "0.0.0.0"
             vt.addrFrom.port = 0
             # Will be sent soon after connection_made
             self.on_connection_send_msg = vt
 
         return create_conn
 
     # Message receiving methods
 
     def on_message(self, message):
         """Receive message and dispatch message to appropriate callback.
 
         We keep a count of how many of each message type has been received
         and the most recent message of each type."""
         with mininode_lock:
             try:
                 command = message.command.decode('ascii')
                 self.message_count[command] += 1
                 self.last_message[command] = message
                 getattr(self, 'on_' + command)(message)
             except Exception:
                 print("ERROR delivering {} ({})".format(
                     repr(message), sys.exc_info()[0]))
                 raise
 
     # Callback methods. Can be overridden by subclasses in individual test
     # cases to provide custom message handling behaviour.
 
     def on_open(self):
         pass
 
     def on_close(self):
         pass
 
     def on_addr(self, message): pass
 
     def on_avapoll(self, message): pass
 
     def on_avaresponse(self, message): pass
 
     def on_block(self, message): pass
 
     def on_blocktxn(self, message): pass
 
     def on_cmpctblock(self, message): pass
 
     def on_feefilter(self, message): pass
 
     def on_getaddr(self, message): pass
 
     def on_getblocks(self, message): pass
 
     def on_getblocktxn(self, message): pass
 
     def on_getdata(self, message): pass
 
     def on_getheaders(self, message): pass
 
     def on_headers(self, message): pass
 
     def on_mempool(self, message): pass
 
     def on_notfound(self, message): pass
 
     def on_pong(self, message): pass
 
     def on_reject(self, message): pass
 
     def on_sendcmpct(self, message): pass
 
     def on_sendheaders(self, message): pass
 
     def on_tx(self, message): pass
 
     def on_inv(self, message):
         want = msg_getdata()
         for i in message.inv:
             if i.type != 0:
                 want.inv.append(i)
         if len(want.inv):
             self.send_message(want)
 
     def on_ping(self, message):
         self.send_message(msg_pong(message.nonce))
 
     def on_verack(self, message):
         self.verack_received = True
 
     def on_version(self, message):
         assert message.nVersion >= MIN_VERSION_SUPPORTED, "Version {} received. Test framework only supports versions greater than {}".format(
             message.nVersion, MIN_VERSION_SUPPORTED)
         self.send_message(msg_verack())
         self.nServices = message.nServices
 
     # Connection helper methods
 
     def wait_for_disconnect(self, timeout=60):
         def test_function(): return not self.is_connected
         wait_until(test_function, timeout=timeout, lock=mininode_lock)
 
     # Message receiving helper methods
 
     def wait_for_block(self, blockhash, timeout=60):
         def test_function(): return self.last_message.get(
             "block") and self.last_message["block"].block.rehash() == blockhash
         wait_until(test_function, timeout=timeout, lock=mininode_lock)
 
     def wait_for_header(self, blockhash, timeout=60):
         def test_function():
             last_headers = self.last_message.get('headers')
             if not last_headers:
                 return False
             return last_headers.headers[0].rehash() == blockhash
 
         wait_until(test_function, timeout=timeout, lock=mininode_lock)
 
     def wait_for_getdata(self, timeout=60):
         """Waits for a getdata message.
 
         Receiving any getdata message will satisfy the predicate. the last_message["getdata"]
         value must be explicitly cleared before calling this method, or this will return
         immediately with success. TODO: change this method to take a hash value and only
         return true if the correct block/tx has been requested."""
         def test_function(): return self.last_message.get("getdata")
         wait_until(test_function, timeout=timeout, lock=mininode_lock)
 
     def wait_for_getheaders(self, timeout=60):
         """Waits for a getheaders message.
 
         Receiving any getheaders message will satisfy the predicate. the last_message["getheaders"]
         value must be explicitly cleared before calling this method, or this will return
         immediately with success. TODO: change this method to take a hash value and only
         return true if the correct block header has been requested."""
         def test_function(): return self.last_message.get("getheaders")
         wait_until(test_function, timeout=timeout, lock=mininode_lock)
 
     def wait_for_inv(self, expected_inv, timeout=60):
         """Waits for an INV message and checks that the first inv object in the message was as expected."""
         if len(expected_inv) > 1:
             raise NotImplementedError(
                 "wait_for_inv() will only verify the first inv object")
 
         def test_function(): return self.last_message.get("inv") and \
             self.last_message["inv"].inv[0].type == expected_inv[0].type and \
             self.last_message["inv"].inv[0].hash == expected_inv[0].hash
         wait_until(test_function, timeout=timeout, lock=mininode_lock)
 
     def wait_for_verack(self, timeout=60):
         def test_function(): return self.message_count["verack"]
         wait_until(test_function, timeout=timeout, lock=mininode_lock)
 
     # Message sending helper functions
 
     def send_and_ping(self, message, timeout=60):
         self.send_message(message)
         self.sync_with_ping(timeout=timeout)
 
     # Sync up with the node
     def sync_with_ping(self, timeout=60):
         self.send_message(msg_ping(nonce=self.ping_counter))
 
         def test_function():
             if not self.last_message.get("pong"):
                 return False
             return self.last_message["pong"].nonce == self.ping_counter
         wait_until(test_function, timeout=timeout, lock=mininode_lock)
         self.ping_counter += 1
 
 
 # One lock for synchronizing all data access between the networking thread (see
 # NetworkThread below) and the thread running the test logic.  For simplicity,
 # P2PConnection acquires this lock whenever delivering a message to a P2PInterface.
 # This lock should be acquired in the thread running the test logic to synchronize
 # access to any data shared with the P2PInterface or P2PConnection.
 mininode_lock = threading.RLock()
 
 
 class NetworkThread(threading.Thread):
     network_event_loop = None
 
     def __init__(self):
         super().__init__(name="NetworkThread")
         # There is only one event loop and no more than one thread must be
         # created
         assert not self.network_event_loop
 
         NetworkThread.network_event_loop = asyncio.new_event_loop()
 
     def run(self):
         """Start the network thread."""
         self.network_event_loop.run_forever()
 
     def close(self, timeout=10):
         """Close the connections and network event loop."""
         self.network_event_loop.call_soon_threadsafe(
             self.network_event_loop.stop)
         wait_until(lambda: not self.network_event_loop.is_running(),
                    timeout=timeout)
         self.network_event_loop.close()
         self.join(timeout)
 
 
 class P2PDataStore(P2PInterface):
     """A P2P data store class.
 
     Keeps a block and transaction store and responds correctly to getdata and getheaders requests."""
 
     def __init__(self):
         super().__init__()
         # store of blocks. key is block hash, value is a CBlock object
         self.block_store = {}
         self.last_block_hash = ''
         # store of txs. key is txid, value is a CTransaction object
         self.tx_store = {}
         self.getdata_requests = []
 
     def on_getdata(self, message):
         """Check for the tx/block in our stores and if found, reply with an inv message."""
         for inv in message.inv:
             self.getdata_requests.append(inv.hash)
             if (inv.type & MSG_TYPE_MASK) == MSG_TX and inv.hash in self.tx_store.keys():
                 self.send_message(msg_tx(self.tx_store[inv.hash]))
             elif (inv.type & MSG_TYPE_MASK) == MSG_BLOCK and inv.hash in self.block_store.keys():
                 self.send_message(msg_block(self.block_store[inv.hash]))
             else:
                 logger.debug(
                     'getdata message type {} received.'.format(hex(inv.type)))
 
     def on_getheaders(self, message):
         """Search back through our block store for the locator, and reply with a headers message if found."""
 
         locator, hash_stop = message.locator, message.hashstop
 
         # Assume that the most recent block added is the tip
         if not self.block_store:
             return
 
         headers_list = [self.block_store[self.last_block_hash]]
         maxheaders = 2000
         while headers_list[-1].sha256 not in locator.vHave:
             # Walk back through the block store, adding headers to headers_list
             # as we go.
             prev_block_hash = headers_list[-1].hashPrevBlock
             if prev_block_hash in self.block_store:
                 prev_block_header = CBlockHeader(
                     self.block_store[prev_block_hash])
                 headers_list.append(prev_block_header)
                 if prev_block_header.sha256 == hash_stop:
                     # if this is the hashstop header, stop here
                     break
             else:
                 logger.debug('block hash {} not found in block store'.format(
                     hex(prev_block_hash)))
                 break
 
         # Truncate the list if there are too many headers
         headers_list = headers_list[:-maxheaders - 1:-1]
         response = msg_headers(headers_list)
 
         if response is not None:
             self.send_message(response)
 
     def send_blocks_and_test(self, blocks, node, *, success=True, request_block=True,
                              reject_reason=None, expect_disconnect=False, timeout=60):
         """Send blocks to test node and test whether the tip advances.
 
          - add all blocks to our block_store
          - send a headers message for the final block
          - the on_getheaders handler will ensure that any getheaders are responded to
          - if request_block is True: wait for getdata for each of the blocks. The on_getdata handler will
            ensure that any getdata messages are responded to
          - if success is True: assert that the node's tip advances to the most recent block
          - if success is False: assert that the node's tip doesn't advance
          - if reject_reason is set: assert that the correct reject message is logged"""
 
         with mininode_lock:
             for block in blocks:
                 self.block_store[block.sha256] = block
                 self.last_block_hash = block.sha256
 
         def test():
             self.send_message(msg_headers([CBlockHeader(blocks[-1])]))
 
             if request_block:
                 wait_until(
                     lambda: blocks[-1].sha256 in self.getdata_requests, timeout=timeout, lock=mininode_lock)
 
             if expect_disconnect:
                 self.wait_for_disconnect(timeout=timeout)
             else:
                 self.sync_with_ping(timeout=timeout)
 
             if success:
                 wait_until(lambda: node.getbestblockhash() ==
                            blocks[-1].hash, timeout=timeout)
             else:
                 assert node.getbestblockhash() != blocks[-1].hash
 
         if reject_reason:
             with node.assert_debug_log(expected_msgs=[reject_reason]):
                 test()
         else:
             test()
 
     def send_txs_and_test(self, txs, node, *, success=True,
                           expect_disconnect=False, reject_reason=None):
         """Send txs to test node and test whether they're accepted to the mempool.
 
          - add all txs to our tx_store
          - send tx messages for all txs
          - if success is True/False: assert that the txs are/are not accepted to the mempool
          - if expect_disconnect is True: Skip the sync with ping
          - if reject_reason is set: assert that the correct reject message is logged."""
 
         with mininode_lock:
             for tx in txs:
                 self.tx_store[tx.sha256] = tx
 
         def test():
             for tx in txs:
                 self.send_message(msg_tx(tx))
 
             if expect_disconnect:
                 self.wait_for_disconnect()
             else:
                 self.sync_with_ping()
 
             raw_mempool = node.getrawmempool()
             if success:
                 # Check that all txs are now in the mempool
                 for tx in txs:
                     assert tx.hash in raw_mempool, "{} not found in mempool".format(
                         tx.hash)
             else:
                 # Check that none of the txs are now in the mempool
                 for tx in txs:
                     assert tx.hash not in raw_mempool, "{} tx found in mempool".format(
                         tx.hash)
 
         if reject_reason:
             with node.assert_debug_log(expected_msgs=[reject_reason]):
                 test()
         else:
             test()