Create SingleNodeConnCB class for RPC tests

(cherry picked from commit 5fa66e4682a59047d2ed2934760ccc052fd85f50)

qa/rpc-tests/maxuploadtarget.py

@@ -7,7 +7,6 @@
 from test_framework.mininode import *
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import *
-from test_framework.comptool import wait_until
 import time
 
 '''

qa/rpc-tests/test_framework/comptool.py

@@ -27,20 +27,6 @@ generator that returns TestInstance objects.  See below for definition.
 
 global mininode_lock
 
-def wait_until(predicate, attempts=float('inf'), timeout=float('inf')):
-    attempt = 0
-    elapsed = 0
-
-    while attempt < attempts and elapsed < timeout:
-        with mininode_lock:
-            if predicate():
-                return True
-        attempt += 1
-        elapsed += 0.05
-        time.sleep(0.05)
-
-    return False
-
 class RejectResult(object):
     '''
     Outcome that expects rejection of a transaction or block.

qa/rpc-tests/test_framework/mininode.py

@@ -1009,6 +1009,21 @@ class msg_reject(object):
         return "msg_reject: %s %d %s [%064x]" \
             % (self.message, self.code, self.reason, self.data)
 
+# Helper function
+def wait_until(predicate, attempts=float('inf'), timeout=float('inf')):
+    attempt = 0
+    elapsed = 0
+
+    while attempt < attempts and elapsed < timeout:
+        with mininode_lock:
+            if predicate():
+                return True
+        attempt += 1
+        elapsed += 0.05
+        time.sleep(0.05)
+
+    return False
+
 # This is what a callback should look like for NodeConn
 # Reimplement the on_* functions to provide handling for events
 class NodeConnCB(object):
@@ -1085,6 +1100,32 @@ class NodeConnCB(object):
     def on_mempool(self, conn): pass
     def on_pong(self, conn, message): pass
 
+# More useful callbacks and functions for NodeConnCB's which have a single NodeConn
+class SingleNodeConnCB(NodeConnCB):
+    def __init__(self):
+        NodeConnCB.__init__(self)
+        self.connection = None
+        self.ping_counter = 1
+        self.last_pong = msg_pong()
+
+    def add_connection(self, conn):
+        self.connection = conn
+
+    # Wrapper for the NodeConn's send_message function
+    def send_message(self, message):
+        self.connection.send_message(message)
+
+    def on_pong(self, conn, message):
+        self.last_pong = message
+
+    # Sync up with the node
+    def sync_with_ping(self, timeout=30):
+        def received_pong():
+            return (self.last_pong.nonce == self.ping_counter)
+        self.send_message(msg_ping(nonce=self.ping_counter))
+        success = wait_until(received_pong, timeout)
+        self.ping_counter += 1
+        return success
 
 # The actual NodeConn class
 # This class provides an interface for a p2p connection to a specified node