test: Disable automatic connections by default

Summary:
```
This prevents the node from trying to connect to random IPs on the internet while running the functional tests. Exceptions are added when required for the test to pass.
```

Backport of [[bitcoin/bitcoin#22490 | core#22490]].

Ref T1696.

Test Plan:
  ninja all check-all

Reviewers: #bitcoin_abc, PiRK

Reviewed By: #bitcoin_abc, PiRK

Maniphest Tasks: T1696

Differential Revision: https://reviews.bitcoinabc.org/D10966

test/functional/feature_anchors.py

@@ -23,6 +23,7 @@ def check_node_connections(*, node, num_in, num_out):
 class AnchorsTest(BitcoinTestFramework):
     def set_test_params(self):
         self.num_nodes = 1
+        self.disable_autoconnect = False
 
     def setup_network(self):
         self.setup_nodes()

test/functional/feature_config_args.py

@@ -16,6 +16,7 @@ def set_test_params(self):
         self.num_nodes = 1
         self.supports_cli = False
         self.wallet_names = []
+        self.disable_autoconnect = False
 
     def test_config_file_parser(self):
         self.stop_node(0)

test/functional/test_framework/test_framework.py

@@ -113,6 +113,9 @@ def __init__(self):
         # skipped. If list is truncated, wallet creation is skipped and keys
         # are not imported.
         self.wallet_names = None
+        # Disable ThreadOpenConnections by default, so that adding entries to
+        # addrman will not result in automatic connections to them.
+        self.disable_autoconnect = True
         self.set_test_params()
         if self.options.timeout_factor == 0:
             self.options.timeout_factor = 99999
@@ -722,7 +725,8 @@ def _initialize_chain(self):
             initialize_datadir(
                 self.options.cachedir,
                 CACHE_NODE_ID,
-                self.chain)
+                self.chain,
+                self.disable_autoconnect)
             self.nodes.append(
                 TestNode(
                     CACHE_NODE_ID,
@@ -793,15 +797,23 @@ def cache_path(*paths):
             to_dir = get_datadir_path(self.options.tmpdir, i)
             shutil.copytree(cache_node_dir, to_dir)
             # Overwrite port/rpcport in bitcoin.conf
-            initialize_datadir(self.options.tmpdir, i, self.chain)
+            initialize_datadir(
+                self.options.tmpdir,
+                i,
+                self.chain,
+                self.disable_autoconnect)
 
     def _initialize_chain_clean(self):
         """Initialize empty blockchain for use by the test.
 
         Create an empty blockchain and num_nodes wallets.
         Useful if a test case wants complete control over initialization."""
         for i in range(self.num_nodes):
-            initialize_datadir(self.options.tmpdir, i, self.chain)
+            initialize_datadir(
+                self.options.tmpdir,
+                i,
+                self.chain,
+                self.disable_autoconnect)
 
     def skip_if_no_py3_zmq(self):
         """Attempt to import the zmq package and skip the test if the import fails."""

test/functional/test_framework/util.py

@@ -355,7 +355,7 @@ def rpc_url(datadir, chain, host, port):
 ################
 
 
-def initialize_datadir(dirname, n, chain):
+def initialize_datadir(dirname, n, chain, disable_autoconnect=True):
     datadir = get_datadir_path(dirname, n)
     if not os.path.isdir(datadir):
         os.makedirs(datadir)
@@ -385,6 +385,8 @@ def initialize_datadir(dirname, n, chain):
         # tests.
         f.write("peertimeout=999999\n")
         f.write("shrinkdebugfile=0\n")
+        if disable_autoconnect:
+            f.write("connect=0\n")
         os.makedirs(os.path.join(datadir, 'stderr'), exist_ok=True)
         os.makedirs(os.path.join(datadir, 'stdout'), exist_ok=True)
     return datadir