Merge bitcoin/bitcoin#22118: test: check anchors.dat when node starts for the first time

ef99d03c2bbb6b5fa5ff3d3d3cb9c5da7d471133 test: check anchors.dat when node starts for the first time (bruno)

Pull request description:

  See https://github.com/bitcoin/bitcoin/pull/21338#discussion_r598406712, https://github.com/bitcoin/bitcoin/pull/21338#discussion_r598406187, https://github.com/bitcoin/bitcoin/pull/21338#discussion_r598405613.

ACKs for top commit:
  laanwj:
    Code review ACK ef99d03c2bbb6b5fa5ff3d3d3cb9c5da7d471133

Tree-SHA512: 505f1f34fbc0c72a92968883be0f1c5f169a4ba3aa8a56e1ce8bc5e514f49e3a17ce51fd40be0073dc4bc06eaeda36dfe90ace843c181170e34643226afd78ef

1 files changed, 19 insertions, 13 deletions

diff --git a/test/functional/feature_anchors.py b/test/functional/feature_anchors.py
index a60a723b3e..24bb02bc90 100755
--- a/test/functional/feature_anchors.py
+++ b/test/functional/feature_anchors.py
@@ -2,7 +2,7 @@
 # Copyright (c) 2020 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 Anchors functionality"""
+"""Test block-relay-only anchors functionality"""
 
 import os
 
@@ -10,6 +10,9 @@ from test_framework.p2p import P2PInterface
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import assert_equal
 
+INBOUND_CONNECTIONS = 5
+BLOCK_RELAY_CONNECTIONS = 2
+
 
 def check_node_connections(*, node, num_in, num_out):
     info = node.getnetworkinfo()
@@ -25,19 +28,26 @@ class AnchorsTest(BitcoinTestFramework):
         self.setup_nodes()
 
     def run_test(self):
-        self.log.info("Add 2 block-relay-only connections to node 0")
-        for i in range(2):
+        node_anchors_path = os.path.join(
+            self.nodes[0].datadir, "regtest", "anchors.dat"
+        )
+
+        self.log.info("When node starts, check if anchors.dat doesn't exist")
+        assert not os.path.exists(node_anchors_path)
+
+        self.log.info(f"Add {BLOCK_RELAY_CONNECTIONS} block-relay-only connections to node")
+        for i in range(BLOCK_RELAY_CONNECTIONS):
             self.log.debug(f"block-relay-only: {i}")
             self.nodes[0].add_outbound_p2p_connection(
                 P2PInterface(), p2p_idx=i, connection_type="block-relay-only"
             )
 
-        self.log.info("Add 5 inbound connections to node 0")
-        for i in range(5):
+        self.log.info(f"Add {INBOUND_CONNECTIONS} inbound connections to node")
+        for i in range(INBOUND_CONNECTIONS):
             self.log.debug(f"inbound: {i}")
             self.nodes[0].add_p2p_connection(P2PInterface())
 
-        self.log.info("Check node 0 connections")
+        self.log.info("Check node connections")
         check_node_connections(node=self.nodes[0], num_in=5, num_out=2)
 
         # 127.0.0.1
@@ -57,14 +67,10 @@ class AnchorsTest(BitcoinTestFramework):
         self.log.info("Stop node 0")
         self.stop_node(0)
 
-        node0_anchors_path = os.path.join(
-            self.nodes[0].datadir, "regtest", "anchors.dat"
-        )
-
         # It should contain only the block-relay-only addresses
         self.log.info("Check the addresses in anchors.dat")
 
-        with open(node0_anchors_path, "rb") as file_handler:
+        with open(node_anchors_path, "rb") as file_handler:
             anchors = file_handler.read().hex()
 
         for port in block_relay_nodes_port:
@@ -74,11 +80,11 @@ class AnchorsTest(BitcoinTestFramework):
             ip_port = ip + port
             assert ip_port not in anchors
 
-        self.log.info("Start node 0")
+        self.log.info("Start node")
         self.start_node(0)
 
         self.log.info("When node starts, check if anchors.dat doesn't exist anymore")
-        assert not os.path.exists(node0_anchors_path)
+        assert not os.path.exists(node_anchors_path)
 
 
 if __name__ == "__main__":