test: make feature_bind_port_(discover|externalip).py auto-detect the skip condition

Instead of requiring a run with an explicit `--ihave1111and2222`, detect
if the `1.1.1.1` and `2.2.2.2` addresses are set up and if not, then
skip the test.

To detect whether the addresses are set use `bitcoind` - start it
and ask it to bind on them and see if it will error with
"Unable to bind". Since this is what the tests do anyway, just start
the nodes and see if an exception will be raised like
`FailedToStartError` / "Unable to bind".

This makes it possible for the CI to run
`feature_bind_port_discover.py` and
`feature_bind_port_externalip.py` by just setting up the
addresses, without having to explicitly provide `--ihave1111and2222`.

Author: vasild

test/functional/feature_bind_port_discover.py

@@ -7,6 +7,9 @@
 """
 
 from test_framework.test_framework import BitcoinTestFramework, SkipTest
+from test_framework.test_node import (
+    FailedToStartError,
+)
 from test_framework.util import (
     assert_equal,
     assert_not_equal,
@@ -15,8 +18,8 @@
 )
 
 # We need to bind to a routable address for this test to exercise the relevant code
-# and also must have another routable address on another interface which must not
-# be named "lo" or "lo0".
+# and also must have another routable address. Those addresses must be on an interface
+# that is UP and is not a loopback interface (IFF_LOOPBACK).
 # To set these routable addresses on the machine, use:
 # Linux:
 # First find your interfaces: ip addr show
@@ -70,19 +73,28 @@ def setup_nodes(self):
         # False. We do not want any -bind= thus set has_explicit_bind to True.
         for node in self.nodes:
             node.has_explicit_bind = True
-        self.start_nodes()
-
-    def add_options(self, parser):
-        parser.add_argument(
-            "--ihave1111and2222", action='store_true', dest="ihave1111and2222",
-            help=f"Run the test, assuming {ADDR1} and {ADDR2} are configured on the machine",
-            default=False)
 
-    def skip_test_if_missing_module(self):
-        if not self.options.ihave1111and2222:
-            raise SkipTest(
-                f"To run this test make sure that {ADDR1} and {ADDR2} (routable addresses) are "
-                "assigned to the interfaces on this machine and rerun with --ihave1111and2222")
+        try:
+            self.start_nodes()
+        except FailedToStartError as e:
+            for node in self.nodes:
+                if node.running:
+                    if node.rpc_connected:
+                        node.stop_node(wait=node.rpc_timeout)
+                    else:
+                        node.process.kill()
+                        node.process.wait(timeout=node.rpc_timeout)
+                        node.process = None
+                        node.stdout.close()
+                        node.stderr.close()
+                        node.running = False
+            if 'Unable to bind to ' in str(e):
+                raise SkipTest(
+                    f'To run this test make sure that {ADDR1} and {ADDR2} '
+                    '(routable addresses) are assigned to non-loopback '
+                    'interfaces on this machine')
+            else:
+                raise e
 
     def run_test(self):
         self.log.info(

test/functional/feature_bind_port_externalip.py

@@ -7,16 +7,23 @@
 """
 
 from test_framework.test_framework import BitcoinTestFramework, SkipTest
+from test_framework.test_node import (
+    FailedToStartError,
+)
 from test_framework.util import assert_equal, p2p_port
 
-# We need to bind to a routable address for this test to exercise the relevant code.
-# To set a routable address on the machine use:
+# We need to bind to a routable address for this test to exercise the relevant
+# code. Those addresses must be on an interface that is UP and is not a loopback
+# interface (IFF_LOOPBACK).
+# To set these routable addresses on the machine, use:
 # Linux:
-# ifconfig lo:0 1.1.1.1/32 up  # to set up
-# ifconfig lo:0 down  # to remove it, after the test
-# FreeBSD:
-# ifconfig lo0 1.1.1.1/32 alias  # to set up
-# ifconfig lo0 1.1.1.1 -alias  # to remove it, after the test
+# First find your interfaces: ip addr show
+# Then use your actual interface names (replace INTERFACE_NAME with yours):
+# ip addr add 1.1.1.1/32 dev INTERFACE_NAME && ip addr add 2.2.2.2/32 dev INTERFACE_NAME  # to set up
+# ip addr del 1.1.1.1/32 dev INTERFACE_NAME && ip addr del 2.2.2.2/32 dev INTERFACE_NAME  # to remove it
+# FreeBSD and MacOS:
+# ifconfig INTERFACE_NAME 1.1.1.1/32 alias  # to set up
+# ifconfig INTERFACE_NAME 1.1.1.1 -alias  # to remove it, after the test
 ADDR = '1.1.1.1'
 
 # array of tuples [arguments, expected port in localaddresses]
@@ -45,17 +52,36 @@ def set_test_params(self):
         self.num_nodes = len(EXPECTED)
         self.extra_args = list(map(lambda e: e[0], EXPECTED))
 
-    def add_options(self, parser):
-        parser.add_argument(
-            "--ihave1111", action='store_true', dest="ihave1111",
-            help=f"Run the test, assuming {ADDR} is configured on the machine",
-            default=False)
+    def setup_network(self):
+        self.setup_nodes()
 
-    def skip_test_if_missing_module(self):
-        if not self.options.ihave1111:
-            raise SkipTest(
-                f"To run this test make sure that {ADDR} (a routable address) is assigned "
-                "to one of the interfaces on this machine and rerun with --ihave1111")
+    def setup_nodes(self):
+        self.add_nodes(self.num_nodes, self.extra_args)
+        # TestNode.start() will add -bind= to extra_args if has_explicit_bind is
+        # False. We do not want any -bind= thus set has_explicit_bind to True.
+        for node in self.nodes:
+            node.has_explicit_bind = True
+        try:
+            self.start_nodes()
+        except FailedToStartError as e:
+            for node in self.nodes:
+                if node.running:
+                    if node.rpc_connected:
+                        node.stop_node(wait=node.rpc_timeout)
+                    else:
+                        node.process.kill()
+                        node.process.wait(timeout=node.rpc_timeout)
+                        node.process = None
+                        node.stdout.close()
+                        node.stderr.close()
+                        node.running = False
+            if 'Unable to bind to ' in str(e):
+                raise SkipTest(
+                    f'To run this test make sure that {ADDR} '
+                    '(routable address) is assigned to non-loopback '
+                    'interface on this machine')
+            else:
+                raise e
 
     def run_test(self):
         self.log.info("Test the proper port is used for -externalip=")