test: adds seednode functional tests

Adds functional tests to test the interaction between seednode and the AddrMan

test/functional/p2p_seednode.py

@@ -0,0 +1,50 @@
+#!/usr/bin/env python3
+# Copyright (c) 2019-2021 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 seednode interaction with the AddrMan
+"""
+import random
+
+from test_framework.test_framework import BitcoinTestFramework
+
+
+class P2PSeedNodes(BitcoinTestFramework):
+    def set_test_params(self):
+        self.num_nodes = 1
+        self.disable_autoconnect = False
+
+    def test_no_seednode(self):
+        # Check that if no seednode is provided, the node proceeds as usual (without waiting)
+        with self.nodes[0].assert_debug_log(expected_msgs=[], unexpected_msgs=["Empty addrman, adding seednode", "Couldn't connect to peers from addrman after 10 seconds. Adding seednode"], timeout=10):
+            self.restart_node(0)
+
+    def test_seednode_empty_addrman(self):
+        seed_node = "0.0.0.1"
+        # Check that the seednode is added to m_addr_fetches on bootstrap on an empty addrman
+        with self.nodes[0].assert_debug_log(expected_msgs=[f"Empty addrman, adding seednode ({seed_node}) to addrfetch"], timeout=10):
+            self.restart_node(0, extra_args=[f'-seednode={seed_node}'])
+
+    def test_seednode_addrman_unreachable_peers(self):
+        seed_node = "0.0.0.2"
+        # Fill the addrman with unreachable nodes
+        for i in range(10):
+            ip = f"{random.randrange(128,169)}.{random.randrange(1,255)}.{random.randrange(1,255)}.{random.randrange(1,255)}"
+            port = 8333 + i
+            self.nodes[0].addpeeraddress(ip, port)
+
+        # Restart the node so seednode is processed again
+        with self.nodes[0].assert_debug_log(expected_msgs=[f"Couldn't connect to peers from addrman after 10 seconds. Adding seednode ({seed_node}) to addrfetch"], unexpected_msgs=["Empty addrman, adding seednode"], timeout=20):
+            self.restart_node(0, extra_args=[f'-seednode={seed_node}'])
+
+    def run_test(self):
+        self.test_no_seednode()
+        self.test_seednode_empty_addrman()
+        self.test_seednode_addrman_unreachable_peers()
+
+
+if __name__ == '__main__':
+    P2PSeedNodes().main()
+

test/functional/test_runner.py

@@ -391,6 +391,7 @@
     'feature_shutdown.py',
     'wallet_migration.py',
     'p2p_ibd_txrelay.py',
+    'p2p_seednode.py',
     # Don't append tests at the end to avoid merge conflicts
     # Put them in a random line within the section that fits their approximate run-time
 ]