Merge #21338: test: add functional test for anchors.dat

581791c62067403fbeb4e1fd88c1d80549627c94 test: add functional test for anchors.dat (bruno)

Pull request description:

  This PR adds a functional test for anchors.dat.

  It creates a node and adds 2 outbound block-relay-only connections and 5 inbound connections.
  When the node is down, anchors.dat should contain the 2 addresses from the outbound block-relay-only connections.

ACKs for top commit:
  MarcoFalke:
    Concept ACK 581791c62067403fbeb4e1fd88c1d80549627c94
  hebasto:
    ACK 581791c62067403fbeb4e1fd88c1d80549627c94

Tree-SHA512: 77038b09e36ee5ae473a26d6f566c0ed283af258c34df8486706a24f72b05abab621a293ac886d03849bc45bc28be7336137252225b25aff393baa6b5238688c

2 files changed, 86 insertions, 0 deletions

diff --git a/test/functional/feature_anchors.py b/test/functional/feature_anchors.py
new file mode 100755
index 0000000000..a60a723b3e
--- /dev/null
+++ b/test/functional/feature_anchors.py
@@ -0,0 +1,85 @@
+#!/usr/bin/env python3
+# 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"""
+
+import os
+
+from test_framework.p2p import P2PInterface
+from test_framework.test_framework import BitcoinTestFramework
+from test_framework.util import assert_equal
+
+
+def check_node_connections(*, node, num_in, num_out):
+    info = node.getnetworkinfo()
+    assert_equal(info["connections_in"], num_in)
+    assert_equal(info["connections_out"], num_out)
+
+
+class AnchorsTest(BitcoinTestFramework):
+    def set_test_params(self):
+        self.num_nodes = 1
+
+    def setup_network(self):
+        self.setup_nodes()
+
+    def run_test(self):
+        self.log.info("Add 2 block-relay-only connections to node 0")
+        for i in range(2):
+            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.debug(f"inbound: {i}")
+            self.nodes[0].add_p2p_connection(P2PInterface())
+
+        self.log.info("Check node 0 connections")
+        check_node_connections(node=self.nodes[0], num_in=5, num_out=2)
+
+        # 127.0.0.1
+        ip = "7f000001"
+
+        # Since the ip is always 127.0.0.1 for this case,
+        # we store only the port to identify the peers
+        block_relay_nodes_port = []
+        inbound_nodes_port = []
+        for p in self.nodes[0].getpeerinfo():
+            addr_split = p["addr"].split(":")
+            if p["connection_type"] == "block-relay-only":
+                block_relay_nodes_port.append(hex(int(addr_split[1]))[2:])
+            else:
+                inbound_nodes_port.append(hex(int(addr_split[1]))[2:])
+
+        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:
+            anchors = file_handler.read().hex()
+
+        for port in block_relay_nodes_port:
+            ip_port = ip + port
+            assert ip_port in anchors
+        for port in inbound_nodes_port:
+            ip_port = ip + port
+            assert ip_port not in anchors
+
+        self.log.info("Start node 0")
+        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)
+
+
+if __name__ == "__main__":
+    AnchorsTest().main()
diff --git a/test/functional/test_runner.py b/test/functional/test_runner.py
index 79ad2cf161..28d3518715 100755
--- a/test/functional/test_runner.py
+++ b/test/functional/test_runner.py
@@ -279,6 +279,7 @@ BASE_SCRIPTS = [
     'p2p_ping.py',
     'rpc_scantxoutset.py',
     'feature_logging.py',
+    'feature_anchors.py',
     'p2p_node_network_limited.py',
     'p2p_permissions.py',
     'feature_blocksdir.py',