wallet, test: add wallet_deprecated_rbf.py for walletrbf deprecated keys & options

test/functional/test_runner.py

@@ -151,6 +151,7 @@ BASE_SCRIPTS = [
     'wallet_listtransactions.py',
     'wallet_miniscript.py',
     # vv Tests less than 30s vv
+    'wallet_deprecated_rbf.py',
     'p2p_invalid_messages.py',
     'rpc_createmultisig.py',
     'p2p_timeouts.py --v1transport',

test/functional/wallet_deprecated_rbf.py

@@ -0,0 +1,37 @@
+#!/usr/bin/env python3
+# Copyright (c) 2026-present 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 deprecation of RPC calls."""
+from test_framework.util import assert_equal
+from test_framework.test_framework import BitcoinTestFramework
+
+'''
+This test exercises the deprecatedrpc=bip125 flag and deprecated -walletrbf options
+and should be removed when the options are removed post deprecation.
+'''
+class WalletDeprecatedRBFTest(BitcoinTestFramework):
+    def set_test_params(self):
+      self.num_nodes = 1
+      self.setup_clean_chain = True
+      self.extra_args = [[]]
+
+    def skip_test_if_missing_module(self):
+      self.skip_if_no_wallet()
+
+    def run_test(self):
+      self.log.info("Test -deprecatedrpc=bip125 and -walletrbf startup option")
+
+      self.restart_node(0, extra_args=["-walletrbf=0", "-deprecatedrpc=bip125"])
+      node = self.nodes[0]
+      node.createwallet("deprecated_optinrbf")
+      wallet = node.get_wallet_rpc("deprecated_optinrbf")
+      self.generatetoaddress(node, nblocks=101, address=wallet.getnewaddress(), sync_fun=self.no_op)
+      tx = wallet.gettransaction(wallet.sendall(recipients=[wallet.getnewaddress()])["txid"])
+      assert_equal("bip125-replaceable" in tx, True)
+      assert_equal(tx["bip125-replaceable"], "no")
+      self.stop_node(0, expected_stderr="Warning: -walletrbf is deprecated and will be fully removed in the next release.")
+
+
+if __name__ == '__main__':
+    WalletDeprecatedRBFTest(__file__).main()