test: add tests for fundrawtx and sendmany rpcs

If the serialized transaction passed to `fundrawtransaction` contains
duplicates, they will be deserialized and added to the transaction. Add
a test to ensure this behavior is not changed during the refactor.

A user can pass any number of duplicated and unrelated addresses as an
SFFO argument to `sendmany` and the RPC will not throw an error (note,
all the rest of the RPCs which take SFFO as an argument will error if
the user passes duplicates or specifies outputs not present in the
transaction). Add a test to ensure this behavior is not changed during
the refactor.

test/functional/test_runner.py

@@ -333,6 +333,8 @@ BASE_SCRIPTS = [
     'wallet_send.py --descriptors',
     'wallet_sendall.py --legacy-wallet',
     'wallet_sendall.py --descriptors',
+    'wallet_sendmany.py --descriptors',
+    'wallet_sendmany.py --legacy-wallet',
     'wallet_create_tx.py --descriptors',
     'wallet_inactive_hdchains.py --legacy-wallet',
     'wallet_spend_unconfirmed.py',

test/functional/wallet_fundrawtransaction.py

@@ -8,10 +8,13 @@
 from decimal import Decimal
 from itertools import product
 from math import ceil
+from test_framework.address import address_to_scriptpubkey
 
 from test_framework.descriptors import descsum_create
 from test_framework.messages import (
     COIN,
+    CTransaction,
+    CTxOut,
 )
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import (
@@ -147,6 +150,34 @@ class RawTransactionsTest(BitcoinTestFramework):
         self.test_22670()
         self.test_feerate_rounding()
         self.test_input_confs_control()
+        self.test_duplicate_outputs()
+
+    def test_duplicate_outputs(self):
+        self.log.info("Test deserializing and funding a transaction with duplicate outputs")
+        self.nodes[1].createwallet("fundtx_duplicate_outputs")
+        w = self.nodes[1].get_wallet_rpc("fundtx_duplicate_outputs")
+
+        addr = w.getnewaddress(address_type="bech32")
+        self.nodes[0].sendtoaddress(addr, 5)
+        self.generate(self.nodes[0], 1)
+
+        address = self.nodes[0].getnewaddress("bech32")
+        tx = CTransaction()
+        tx.vin = []
+        tx.vout = [CTxOut(1 * COIN, bytearray(address_to_scriptpubkey(address)))] * 2
+        tx.nLockTime = 0
+        tx_hex = tx.serialize().hex()
+        res = w.fundrawtransaction(tx_hex, add_inputs=True)
+        signed_res = w.signrawtransactionwithwallet(res["hex"])
+        txid = w.sendrawtransaction(signed_res["hex"])
+        assert self.nodes[1].getrawtransaction(txid)
+
+        self.log.info("Test SFFO with duplicate outputs")
+
+        res_sffo = w.fundrawtransaction(tx_hex, add_inputs=True, subtractFeeFromOutputs=[0,1])
+        signed_res_sffo = w.signrawtransactionwithwallet(res_sffo["hex"])
+        txid_sffo = w.sendrawtransaction(signed_res_sffo["hex"])
+        assert self.nodes[1].getrawtransaction(txid_sffo)
 
     def test_change_position(self):
         """Ensure setting changePosition in fundraw with an exact match is handled properly."""

test/functional/wallet_sendmany.py

@@ -0,0 +1,43 @@
+#!/usr/bin/env python3
+# Copyright (c) 2022 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 the sendmany RPC command."""
+
+from test_framework.test_framework import BitcoinTestFramework
+
+class SendmanyTest(BitcoinTestFramework):
+    # Setup and helpers
+    def add_options(self, parser):
+        self.add_wallet_options(parser)
+
+
+    def skip_test_if_missing_module(self):
+        self.skip_if_no_wallet()
+
+
+    def set_test_params(self):
+        self.num_nodes = 1
+        self.setup_clean_chain = True
+
+    def test_sffo_repeated_address(self):
+        addr_1 = self.wallet.getnewaddress()
+        addr_2 = self.wallet.getnewaddress()
+        addr_3 = self.wallet.getnewaddress()
+
+        self.log.info("Test using duplicate address in SFFO argument")
+        self.def_wallet.sendmany(dummy='', amounts={addr_1: 1, addr_2: 1}, subtractfeefrom=[addr_1, addr_1, addr_1])
+        self.log.info("Test using address not present in tx.vout in SFFO argument")
+        self.def_wallet.sendmany(dummy='', amounts={addr_1: 1, addr_2: 1}, subtractfeefrom=[addr_3])
+
+    def run_test(self):
+        self.nodes[0].createwallet("activewallet")
+        self.wallet = self.nodes[0].get_wallet_rpc("activewallet")
+        self.def_wallet = self.nodes[0].get_wallet_rpc(self.default_wallet_name)
+        self.generate(self.nodes[0], 101)
+
+        self.test_sffo_repeated_address()
+
+
+if __name__ == '__main__':
+    SendmanyTest().main()