Merge #11345: [tests] Check connectivity before sending in assumevalid.py

e9e939108 [tests] Check connectivity before sending in assumevalid.py (John Newbery)

Pull request description:

  assumevalid.py would try to send over a closed P2P connection in a loop,
  hitting the following failure many times:

  `TestFramework.mininode (ERROR): Cannot send message. No connection to node!`

  The test still passed, but this is a lot of noise in the test log.

  Just check that the connection is open before trying to send.

Tree-SHA512: 6faf2ce5717de976fed1b5c863bc8d17e785928690f833d5bf175178f95d39f455635a844fe7e0dfdad83ae779dd45bc6e4ed89a9467d8482c5be73b55095c8d

test/functional/assumevalid.py

@@ -68,6 +68,8 @@ class AssumeValidTest(BitcoinTestFramework):
     def send_blocks_until_disconnected(self, node):
         """Keep sending blocks to the node until we're disconnected."""
         for i in range(len(self.blocks)):
+            if not node.connection:
+                break
             try:
                 node.send_message(msg_block(self.blocks[i]))
             except IOError as e: