Bitcoin Core  27.99.0
P2P Digital Currency
spend_tests.cpp
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1 // Copyright (c) 2021-2022 The Bitcoin Core developers
2 // Distributed under the MIT software license, see the accompanying
3 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
4 
5 #include <consensus/amount.h>
6 #include <policy/fees.h>
7 #include <script/solver.h>
8 #include <validation.h>
9 #include <wallet/coincontrol.h>
10 #include <wallet/spend.h>
11 #include <wallet/test/util.h>
13 
14 #include <boost/test/unit_test.hpp>
15 
16 namespace wallet {
17 BOOST_FIXTURE_TEST_SUITE(spend_tests, WalletTestingSetup)
18 
20 {
21  CreateAndProcessBlock({}, GetScriptForRawPubKey(coinbaseKey.GetPubKey()));
22  auto wallet = CreateSyncedWallet(*m_node.chain, WITH_LOCK(Assert(m_node.chainman)->GetMutex(), return m_node.chainman->ActiveChain()), coinbaseKey);
23 
24  // Check that a subtract-from-recipient transaction slightly less than the
25  // coinbase input amount does not create a change output (because it would
26  // be uneconomical to add and spend the output), and make sure it pays the
27  // leftover input amount which would have been change to the recipient
28  // instead of the miner.
29  auto check_tx = [&wallet](CAmount leftover_input_amount) {
30  CRecipient recipient{PubKeyDestination({}), 50 * COIN - leftover_input_amount, /*subtract_fee=*/true};
31  CCoinControl coin_control;
32  coin_control.m_feerate.emplace(10000);
33  coin_control.fOverrideFeeRate = true;
34  // We need to use a change type with high cost of change so that the leftover amount will be dropped to fee instead of added as a change output
35  coin_control.m_change_type = OutputType::LEGACY;
36  auto res = CreateTransaction(*wallet, {recipient}, /*change_pos=*/std::nullopt, coin_control);
37  BOOST_CHECK(res);
38  const auto& txr = *res;
39  BOOST_CHECK_EQUAL(txr.tx->vout.size(), 1);
40  BOOST_CHECK_EQUAL(txr.tx->vout[0].nValue, recipient.nAmount + leftover_input_amount - txr.fee);
41  BOOST_CHECK_GT(txr.fee, 0);
42  return txr.fee;
43  };
44 
45  // Send full input amount to recipient, check that only nonzero fee is
46  // subtracted (to_reduce == fee).
47  const CAmount fee{check_tx(0)};
48 
49  // Send slightly less than full input amount to recipient, check leftover
50  // input amount is paid to recipient not the miner (to_reduce == fee - 123)
51  BOOST_CHECK_EQUAL(fee, check_tx(123));
52 
53  // Send full input minus fee amount to recipient, check leftover input
54  // amount is paid to recipient not the miner (to_reduce == 0)
55  BOOST_CHECK_EQUAL(fee, check_tx(fee));
56 
57  // Send full input minus more than the fee amount to recipient, check
58  // leftover input amount is paid to recipient not the miner (to_reduce ==
59  // -123). This overpays the recipient instead of overpaying the miner more
60  // than double the necessary fee.
61  BOOST_CHECK_EQUAL(fee, check_tx(fee + 123));
62 }
63 
64 BOOST_FIXTURE_TEST_CASE(wallet_duplicated_preset_inputs_test, TestChain100Setup)
65 {
66  // Verify that the wallet's Coin Selection process does not include pre-selected inputs twice in a transaction.
67 
68  // Add 4 spendable UTXO, 50 BTC each, to the wallet (total balance 200 BTC)
69  for (int i = 0; i < 4; i++) CreateAndProcessBlock({}, GetScriptForRawPubKey(coinbaseKey.GetPubKey()));
70  auto wallet = CreateSyncedWallet(*m_node.chain, WITH_LOCK(Assert(m_node.chainman)->GetMutex(), return m_node.chainman->ActiveChain()), coinbaseKey);
71 
72  LOCK(wallet->cs_wallet);
73  auto available_coins = AvailableCoins(*wallet);
74  std::vector<COutput> coins = available_coins.All();
75  // Preselect the first 3 UTXO (150 BTC total)
76  std::set<COutPoint> preset_inputs = {coins[0].outpoint, coins[1].outpoint, coins[2].outpoint};
77 
78  // Try to create a tx that spends more than what preset inputs + wallet selected inputs are covering for.
79  // The wallet can cover up to 200 BTC, and the tx target is 299 BTC.
80  std::vector<CRecipient> recipients{{*Assert(wallet->GetNewDestination(OutputType::BECH32, "dummy")),
81  /*nAmount=*/299 * COIN, /*fSubtractFeeFromAmount=*/true}};
82  CCoinControl coin_control;
83  coin_control.m_allow_other_inputs = true;
84  for (const auto& outpoint : preset_inputs) {
85  coin_control.Select(outpoint);
86  }
87 
88  // Attempt to send 299 BTC from a wallet that only has 200 BTC. The wallet should exclude
89  // the preset inputs from the pool of available coins, realize that there is not enough
90  // money to fund the 299 BTC payment, and fail with "Insufficient funds".
91  //
92  // Even with SFFO, the wallet can only afford to send 200 BTC.
93  // If the wallet does not properly exclude preset inputs from the pool of available coins
94  // prior to coin selection, it may create a transaction that does not fund the full payment
95  // amount or, through SFFO, incorrectly reduce the recipient's amount by the difference
96  // between the original target and the wrongly counted inputs (in this case 99 BTC)
97  // so that the recipient's amount is no longer equal to the user's selected target of 299 BTC.
98 
99  // First case, use 'subtract_fee_from_outputs=true'
100  BOOST_CHECK(!CreateTransaction(*wallet, recipients, /*change_pos=*/std::nullopt, coin_control));
101 
102  // Second case, don't use 'subtract_fee_from_outputs'.
103  recipients[0].fSubtractFeeFromAmount = false;
104  BOOST_CHECK(!CreateTransaction(*wallet, recipients, /*change_pos=*/std::nullopt, coin_control));
105 }
106 
108 } // namespace wallet
int64_t CAmount
Amount in satoshis (Can be negative)
Definition: amount.h:12
static constexpr CAmount COIN
The amount of satoshis in one BTC.
Definition: amount.h:15
node::NodeContext m_node
Definition: bitcoin-gui.cpp:37
#define Assert(val)
Identity function.
Definition: check.h:77
Coin Control Features.
Definition: coincontrol.h:81
std::optional< OutputType > m_change_type
Override the default change type if set, ignored if destChange is set.
Definition: coincontrol.h:86
PreselectedInput & Select(const COutPoint &outpoint)
Lock-in the given output for spending.
Definition: coincontrol.cpp:40
bool m_allow_other_inputs
If true, the selection process can add extra unselected inputs from the wallet while requires all sel...
Definition: coincontrol.h:91
bool fOverrideFeeRate
Override automatic min/max checks on fee, m_feerate must be set if true.
Definition: coincontrol.h:95
std::optional< CFeeRate > m_feerate
Override the wallet's m_pay_tx_fee if set.
Definition: coincontrol.h:97
BOOST_AUTO_TEST_SUITE_END()
util::Result< CreatedTransactionResult > CreateTransaction(CWallet &wallet, const std::vector< CRecipient > &vecSend, std::optional< unsigned int > change_pos, const CCoinControl &coin_control, bool sign)
Create a new transaction paying the recipients with a set of coins selected by SelectCoins(); Also cr...
Definition: spend.cpp:1333
BOOST_FIXTURE_TEST_CASE(wallet_coinsresult_test, BasicTestingSetup)
std::unique_ptr< CWallet > CreateSyncedWallet(interfaces::Chain &chain, CChain &cchain, const CKey &key)
Definition: util.cpp:20
CoinsResult AvailableCoins(const CWallet &wallet, const CCoinControl *coinControl, std::optional< CFeeRate > feerate, const CoinFilterParams &params)
Populate the CoinsResult struct with vectors of available COutputs, organized by OutputType.
Definition: spend.cpp:305
std::shared_ptr< CWallet > wallet
#define BOOST_CHECK_EQUAL(v1, v2)
Definition: object.cpp:18
#define BOOST_CHECK(expr)
Definition: object.cpp:17
CScript GetScriptForRawPubKey(const CPubKey &pubKey)
Generate a P2PK script for the given pubkey.
Definition: solver.cpp:209
Testing fixture that pre-creates a 100-block REGTEST-mode block chain.
Definition: setup_common.h:106
std::unique_ptr< ChainstateManager > chainman
Definition: context.h:67
std::unique_ptr< interfaces::Chain > chain
Definition: context.h:71
#define LOCK(cs)
Definition: sync.h:257
#define WITH_LOCK(cs, code)
Run code while locking a mutex.
Definition: sync.h:301