LCOV - code coverage report
Current view: top level - src/wallet/test - coinselector_tests.cpp (source / functions) Coverage Total Hit
Test: total_coverage.info Lines: 97.8 % 898 878
Test Date: 2025-09-13 05:20:27 Functions: 100.0 % 55 55
Branches: 51.9 % 3038 1577

             Branch data     Line data    Source code
       1                 :             : // Copyright (c) 2017-2022 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 <node/context.h>
       7                 :             : #include <policy/policy.h>
       8                 :             : #include <primitives/transaction.h>
       9                 :             : #include <random.h>
      10                 :             : #include <test/util/setup_common.h>
      11                 :             : #include <util/translation.h>
      12                 :             : #include <wallet/coincontrol.h>
      13                 :             : #include <wallet/coinselection.h>
      14                 :             : #include <wallet/spend.h>
      15                 :             : #include <wallet/test/util.h>
      16                 :             : #include <wallet/test/wallet_test_fixture.h>
      17                 :             : #include <wallet/wallet.h>
      18                 :             : 
      19                 :             : #include <algorithm>
      20                 :             : #include <boost/test/unit_test.hpp>
      21                 :             : #include <random>
      22                 :             : 
      23                 :             : namespace wallet {
      24                 :             : BOOST_FIXTURE_TEST_SUITE(coinselector_tests, WalletTestingSetup)
      25                 :             : 
      26                 :             : // how many times to run all the tests to have a chance to catch errors that only show up with particular random shuffles
      27                 :             : #define RUN_TESTS 100
      28                 :             : 
      29                 :             : // some tests fail 1% of the time due to bad luck.
      30                 :             : // we repeat those tests this many times and only complain if all iterations of the test fail
      31                 :             : #define RANDOM_REPEATS 5
      32                 :             : 
      33                 :             : typedef std::set<std::shared_ptr<COutput>> CoinSet;
      34                 :             : 
      35                 :             : static const CoinEligibilityFilter filter_standard(1, 6, 0);
      36                 :             : static const CoinEligibilityFilter filter_confirmed(1, 1, 0);
      37                 :             : static const CoinEligibilityFilter filter_standard_extra(6, 6, 0);
      38                 :             : static int nextLockTime = 0;
      39                 :             : 
      40                 :          43 : static void add_coin(const CAmount& nValue, int nInput, SelectionResult& result)
      41                 :             : {
      42                 :          43 :     CMutableTransaction tx;
      43         [ +  - ]:          43 :     tx.vout.resize(nInput + 1);
      44         [ +  - ]:          43 :     tx.vout[nInput].nValue = nValue;
      45                 :          43 :     tx.nLockTime = nextLockTime++;        // so all transactions get different hashes
      46   [ +  -  +  -  :          43 :     COutput output(COutPoint(tx.GetHash(), nInput), tx.vout.at(nInput), /*depth=*/1, /*input_bytes=*/-1, /*solvable=*/true, /*safe=*/true, /*time=*/0, /*from_me=*/false, /*fees=*/ 0);
                   +  - ]
      47         [ +  - ]:          43 :     OutputGroup group;
      48   [ +  -  +  - ]:          43 :     group.Insert(std::make_shared<COutput>(output), /*ancestors=*/ 0, /*descendants=*/ 0);
      49         [ +  - ]:          43 :     result.AddInput(group);
      50                 :          86 : }
      51                 :             : 
      52                 :          28 : static void add_coin(const CAmount& nValue, int nInput, SelectionResult& result, CAmount fee, CAmount long_term_fee)
      53                 :             : {
      54                 :          28 :     CMutableTransaction tx;
      55         [ +  - ]:          28 :     tx.vout.resize(nInput + 1);
      56         [ +  - ]:          28 :     tx.vout[nInput].nValue = nValue;
      57                 :          28 :     tx.nLockTime = nextLockTime++;        // so all transactions get different hashes
      58   [ +  -  +  -  :          28 :     std::shared_ptr<COutput> coin = std::make_shared<COutput>(COutPoint(tx.GetHash(), nInput), tx.vout.at(nInput), /*depth=*/1, /*input_bytes=*/148, /*solvable=*/true, /*safe=*/true, /*time=*/0, /*from_me=*/false, fee);
                   +  - ]
      59         [ +  - ]:          28 :     OutputGroup group;
      60         [ +  - ]:          28 :     group.Insert(coin, /*ancestors=*/ 0, /*descendants=*/ 0);
      61         [ +  - ]:          28 :     coin->long_term_fee = long_term_fee; // group.Insert() will modify long_term_fee, so we need to set it afterwards
      62         [ +  - ]:          28 :     result.AddInput(group);
      63         [ +  - ]:          84 : }
      64                 :             : 
      65                 :      116191 : static void add_coin(CoinsResult& available_coins, CWallet& wallet, const CAmount& nValue, CFeeRate feerate = CFeeRate(0), int nAge = 6*24, bool fIsFromMe = false, int nInput =0, bool spendable = false, int custom_size = 0)
      66                 :             : {
      67                 :      116191 :     CMutableTransaction tx;
      68                 :      116191 :     tx.nLockTime = nextLockTime++;        // so all transactions get different hashes
      69         [ +  - ]:      116191 :     tx.vout.resize(nInput + 1);
      70         [ +  + ]:      116191 :     tx.vout[nInput].nValue = nValue;
      71         [ +  + ]:      116191 :     if (spendable) {
      72   [ +  -  +  -  :        6152 :         tx.vout[nInput].scriptPubKey = GetScriptForDestination(*Assert(wallet.GetNewDestination(OutputType::BECH32, "")));
             +  -  +  - ]
      73                 :             :     }
      74         [ +  - ]:      116191 :     Txid txid = tx.GetHash();
      75                 :             : 
      76         [ +  - ]:      116191 :     LOCK(wallet.cs_wallet);
      77   [ +  -  +  -  :      232382 :     auto ret = wallet.mapWallet.emplace(std::piecewise_construct, std::forward_as_tuple(txid), std::forward_as_tuple(MakeTransactionRef(std::move(tx)), TxStateInactive{}));
                   -  + ]
      78         [ -  + ]:      116191 :     assert(ret.second);
      79         [ +  - ]:      116191 :     CWalletTx& wtx = (*ret.first).second;
      80         [ +  - ]:      116191 :     const auto& txout = wtx.tx->vout.at(nInput);
      81   [ +  +  +  -  :      232382 :     available_coins.Add(OutputType::BECH32, {COutPoint(wtx.GetHash(), nInput), txout, nAge, custom_size == 0 ? CalculateMaximumSignedInputSize(txout, &wallet, /*coin_control=*/nullptr) : custom_size, /*solvable=*/true, /*safe=*/true, wtx.GetTxTime(), fIsFromMe, feerate});
          +  -  +  -  +  
                -  +  - ]
      82                 :      232382 : }
      83                 :             : 
      84                 :             : // Helpers
      85                 :        5601 : std::optional<SelectionResult> KnapsackSolver(std::vector<OutputGroup>& groups, const CAmount& nTargetValue,
      86                 :             :                                               CAmount change_target, FastRandomContext& rng)
      87                 :             : {
      88                 :        5601 :     auto res{KnapsackSolver(groups, nTargetValue, change_target, rng, MAX_STANDARD_TX_WEIGHT)};
      89   [ +  +  +  - ]:       10602 :     return res ? std::optional<SelectionResult>(*res) : std::nullopt;
      90                 :        5601 : }
      91                 :             : 
      92                 :           3 : std::optional<SelectionResult> SelectCoinsBnB(std::vector<OutputGroup>& utxo_pool, const CAmount& selection_target, const CAmount& cost_of_change)
      93                 :             : {
      94                 :           3 :     auto res{SelectCoinsBnB(utxo_pool, selection_target, cost_of_change, MAX_STANDARD_TX_WEIGHT)};
      95   [ +  +  +  - ]:           5 :     return res ? std::optional<SelectionResult>(*res) : std::nullopt;
      96                 :           3 : }
      97                 :             : 
      98                 :             : /** Check if SelectionResult a is equivalent to SelectionResult b.
      99                 :             :  * Equivalent means same input values, but maybe different inputs (i.e. same value, different prevout) */
     100                 :           7 : static bool EquivalentResult(const SelectionResult& a, const SelectionResult& b)
     101                 :             : {
     102                 :           7 :     std::vector<CAmount> a_amts;
     103                 :           7 :     std::vector<CAmount> b_amts;
     104   [ +  -  +  + ]:          50 :     for (const auto& coin : a.GetInputSet()) {
     105         [ +  - ]:          43 :         a_amts.push_back(coin->txout.nValue);
     106                 :             :     }
     107   [ +  -  +  + ]:          50 :     for (const auto& coin : b.GetInputSet()) {
     108         [ +  - ]:          43 :         b_amts.push_back(coin->txout.nValue);
     109                 :             :     }
     110                 :           7 :     std::sort(a_amts.begin(), a_amts.end());
     111                 :           7 :     std::sort(b_amts.begin(), b_amts.end());
     112                 :             : 
     113                 :           7 :     std::pair<std::vector<CAmount>::iterator, std::vector<CAmount>::iterator> ret = std::mismatch(a_amts.begin(), a_amts.end(), b_amts.begin());
     114   [ +  -  -  + ]:           7 :     return ret.first == a_amts.end() && ret.second == b_amts.end();
     115                 :           7 : }
     116                 :             : 
     117                 :             : /** Check if this selection is equal to another one. Equal means same inputs (i.e same value and prevout) */
     118                 :        1100 : static bool EqualResult(const SelectionResult& a, const SelectionResult& b)
     119                 :             : {
     120                 :        1100 :     std::pair<CoinSet::iterator, CoinSet::iterator> ret = std::mismatch(a.GetInputSet().begin(), a.GetInputSet().end(), b.GetInputSet().begin(),
     121                 :        1100 :         [](const std::shared_ptr<COutput>& a, const std::shared_ptr<COutput>& b) {
     122         [ +  + ]:        1100 :             return a->outpoint == b->outpoint;
     123                 :             :         });
     124   [ +  +  -  + ]:        1100 :     return ret.first == a.GetInputSet().end() && ret.second == b.GetInputSet().end();
     125                 :             : }
     126                 :             : 
     127                 :        2204 : inline std::vector<OutputGroup>& GroupCoins(const std::vector<COutput>& available_coins, bool subtract_fee_outputs = false)
     128                 :             : {
     129   [ +  +  +  - ]:        2205 :     static std::vector<OutputGroup> static_groups;
     130                 :        2204 :     static_groups.clear();
     131         [ +  + ]:      227219 :     for (auto& coin : available_coins) {
     132                 :      225015 :         static_groups.emplace_back();
     133                 :      225015 :         OutputGroup& group = static_groups.back();
     134         [ +  - ]:      225015 :         group.Insert(std::make_shared<COutput>(coin), /*ancestors=*/ 0, /*descendants=*/ 0);
     135                 :      225015 :         group.m_subtract_fee_outputs = subtract_fee_outputs;
     136                 :             :     }
     137                 :        2204 :     return static_groups;
     138                 :             : }
     139                 :             : 
     140                 :        3401 : inline std::vector<OutputGroup>& KnapsackGroupOutputs(const CoinsResult& available_coins, CWallet& wallet, const CoinEligibilityFilter& filter)
     141                 :             : {
     142                 :        3401 :     FastRandomContext rand{};
     143         [ +  + ]:        3401 :     CoinSelectionParams coin_selection_params{
     144                 :             :         rand,
     145                 :             :         /*change_output_size=*/ 0,
     146                 :             :         /*change_spend_size=*/ 0,
     147                 :             :         /*min_change_target=*/ CENT,
     148                 :        3401 :         /*effective_feerate=*/ CFeeRate(0),
     149                 :        3401 :         /*long_term_feerate=*/ CFeeRate(0),
     150                 :        3401 :         /*discard_feerate=*/ CFeeRate(0),
     151                 :             :         /*tx_noinputs_size=*/ 0,
     152                 :             :         /*avoid_partial=*/ false,
     153         [ +  + ]:        3401 :     };
     154   [ +  +  +  - ]:        3401 :     static OutputGroupTypeMap static_groups;
     155   [ +  -  +  -  :        6802 :     static_groups = GroupOutputs(wallet, available_coins, coin_selection_params, {{filter}})[filter];
             +  -  +  - ]
     156                 :        3401 :     return static_groups.all_groups.mixed_group;
     157                 :        3401 : }
     158                 :             : 
     159                 :          24 : static std::unique_ptr<CWallet> NewWallet(const node::NodeContext& m_node, const std::string& wallet_name = "")
     160                 :             : {
     161   [ +  -  +  - ]:          24 :     std::unique_ptr<CWallet> wallet = std::make_unique<CWallet>(m_node.chain.get(), wallet_name, CreateMockableWalletDatabase());
     162         [ +  - ]:          24 :     LOCK(wallet->cs_wallet);
     163         [ +  - ]:          24 :     wallet->SetWalletFlag(WALLET_FLAG_DESCRIPTORS);
     164         [ +  - ]:          24 :     wallet->SetupDescriptorScriptPubKeyMans();
     165         [ +  - ]:          24 :     return wallet;
     166                 :          24 : }
     167                 :             : 
     168                 :             : // Branch and bound coin selection tests
     169   [ +  -  +  -  :           7 : BOOST_AUTO_TEST_CASE(bnb_search_test)
          +  -  +  -  -  
          +  +  -  +  -  
          +  -  +  -  +  
          -  +  -  -  +  
          +  -  +  -  +  
          -  +  -  +  -  
          +  -  -  +  +  
          -  +  -  +  -  
          +  -  +  -  +  
          -  +  -  -  +  
          +  -  +  -  +  
          -  +  -  +  -  
          +  -  -  +  +  
                      - ]
     170                 :             : {
     171                 :           1 :     FastRandomContext rand{};
     172                 :             :     // Setup
     173                 :           1 :     std::vector<COutput> utxo_pool;
     174         [ +  - ]:           1 :     SelectionResult expected_result(CAmount(0), SelectionAlgorithm::BNB);
     175                 :             : 
     176                 :             :     ////////////////////
     177                 :             :     // Behavior tests //
     178                 :             :     ////////////////////
     179                 :             : 
     180                 :             :     // Make sure that effective value is working in AttemptSelection when BnB is used
     181         [ +  - ]:           1 :     CoinSelectionParams coin_selection_params_bnb{
     182                 :             :         rand,
     183                 :             :         /*change_output_size=*/ 31,
     184                 :             :         /*change_spend_size=*/ 68,
     185                 :             :         /*min_change_target=*/ 0,
     186                 :           1 :         /*effective_feerate=*/ CFeeRate(3000),
     187                 :           1 :         /*long_term_feerate=*/ CFeeRate(1000),
     188                 :           1 :         /*discard_feerate=*/ CFeeRate(1000),
     189                 :             :         /*tx_noinputs_size=*/ 0,
     190                 :             :         /*avoid_partial=*/ false,
     191         [ +  - ]:           1 :     };
     192         [ +  - ]:           1 :     coin_selection_params_bnb.m_change_fee = coin_selection_params_bnb.m_effective_feerate.GetFee(coin_selection_params_bnb.change_output_size);
     193         [ +  - ]:           1 :     coin_selection_params_bnb.m_cost_of_change = coin_selection_params_bnb.m_effective_feerate.GetFee(coin_selection_params_bnb.change_spend_size) + coin_selection_params_bnb.m_change_fee;
     194         [ +  - ]:           1 :     coin_selection_params_bnb.min_viable_change = coin_selection_params_bnb.m_effective_feerate.GetFee(coin_selection_params_bnb.change_spend_size);
     195                 :             : 
     196                 :           1 :     {
     197   [ +  -  +  - ]:           1 :         std::unique_ptr<CWallet> wallet = NewWallet(m_node);
     198                 :             : 
     199         [ +  - ]:           1 :         CoinsResult available_coins;
     200                 :             : 
     201         [ +  - ]:           1 :         add_coin(available_coins, *wallet, 1, coin_selection_params_bnb.m_effective_feerate);
     202         [ +  - ]:           2 :         available_coins.All().at(0).input_bytes = 40; // Make sure that it has a negative effective value. The next check should assert if this somehow got through. Otherwise it will fail
     203   [ +  -  +  -  :           2 :         BOOST_CHECK(!SelectCoinsBnB(GroupCoins(available_coins.All()), 1 * CENT, coin_selection_params_bnb.m_cost_of_change));
          +  -  +  -  +  
                -  +  - ]
     204                 :             : 
     205                 :             :         // Test fees subtracted from output:
     206         [ +  - ]:           1 :         available_coins.Clear();
     207         [ +  - ]:           1 :         add_coin(available_coins, *wallet, 1 * CENT, coin_selection_params_bnb.m_effective_feerate);
     208         [ +  - ]:           2 :         available_coins.All().at(0).input_bytes = 40;
     209   [ +  -  +  -  :           1 :         const auto result9 = SelectCoinsBnB(GroupCoins(available_coins.All()), 1 * CENT, coin_selection_params_bnb.m_cost_of_change);
                   +  - ]
     210   [ +  -  +  -  :           2 :         BOOST_CHECK(result9);
                   +  - ]
     211   [ +  -  +  -  :           1 :         BOOST_CHECK_EQUAL(result9->GetSelectedValue(), 1 * CENT);
                   +  - ]
     212         [ +  - ]:           1 :     }
     213                 :             : 
     214                 :           1 :     {
     215   [ +  -  +  - ]:           1 :         std::unique_ptr<CWallet> wallet = NewWallet(m_node);
     216                 :             : 
     217         [ +  - ]:           1 :         CoinsResult available_coins;
     218                 :             : 
     219         [ +  - ]:           1 :         coin_selection_params_bnb.m_effective_feerate = CFeeRate(0);
     220         [ +  - ]:           1 :         add_coin(available_coins, *wallet, 5 * CENT, coin_selection_params_bnb.m_effective_feerate, 6 * 24, false, 0, true);
     221         [ +  - ]:           1 :         add_coin(available_coins, *wallet, 3 * CENT, coin_selection_params_bnb.m_effective_feerate, 6 * 24, false, 0, true);
     222         [ +  - ]:           1 :         add_coin(available_coins, *wallet, 2 * CENT, coin_selection_params_bnb.m_effective_feerate, 6 * 24, false, 0, true);
     223         [ +  - ]:           1 :         CCoinControl coin_control;
     224                 :           1 :         coin_control.m_allow_other_inputs = true;
     225         [ +  - ]:           2 :         COutput select_coin = available_coins.All().at(0);
     226         [ +  - ]:           1 :         coin_control.Select(select_coin.outpoint);
     227         [ +  - ]:           1 :         PreSelectedInputs selected_input;
     228         [ +  - ]:           1 :         selected_input.Insert(select_coin, coin_selection_params_bnb.m_subtract_fee_outputs);
     229   [ +  -  +  -  :           3 :         available_coins.Erase({available_coins.coins[OutputType::BECH32].begin()->outpoint});
             +  -  +  - ]
     230                 :             : 
     231         [ +  - ]:           1 :         LOCK(wallet->cs_wallet);
     232         [ +  - ]:           1 :         const auto result10 = SelectCoins(*wallet, available_coins, selected_input, 10 * CENT, coin_control, coin_selection_params_bnb);
     233   [ +  -  +  - ]:           2 :         BOOST_CHECK(result10);
     234   [ +  -  +  - ]:           2 :     }
     235                 :           1 :     {
     236   [ +  -  +  - ]:           1 :         std::unique_ptr<CWallet> wallet = NewWallet(m_node);
     237         [ +  - ]:           1 :         LOCK(wallet->cs_wallet); // Every 'SelectCoins' call requires it
     238                 :             : 
     239         [ +  - ]:           1 :         CoinsResult available_coins;
     240                 :             : 
     241                 :             :         // pre selected coin should be selected even if disadvantageous
     242         [ +  - ]:           1 :         coin_selection_params_bnb.m_effective_feerate = CFeeRate(5000);
     243                 :           1 :         coin_selection_params_bnb.m_long_term_feerate = CFeeRate(3000);
     244                 :             : 
     245                 :             :         // Add selectable outputs, increasing their raw amounts by their input fee to make the effective value equal to the raw amount
     246         [ +  - ]:           1 :         CAmount input_fee = coin_selection_params_bnb.m_effective_feerate.GetFee(/*virtual_bytes=*/68); // bech32 input size (default test output type)
     247         [ +  - ]:           1 :         add_coin(available_coins, *wallet, 10 * CENT + input_fee, coin_selection_params_bnb.m_effective_feerate, 6 * 24, false, 0, true);
     248         [ +  - ]:           1 :         add_coin(available_coins, *wallet, 9 * CENT + input_fee, coin_selection_params_bnb.m_effective_feerate, 6 * 24, false, 0, true);
     249         [ +  - ]:           1 :         add_coin(available_coins, *wallet, 1 * CENT + input_fee, coin_selection_params_bnb.m_effective_feerate, 6 * 24, false, 0, true);
     250                 :             : 
     251         [ +  - ]:           1 :         expected_result.Clear();
     252         [ +  - ]:           1 :         add_coin(9 * CENT + input_fee, 2, expected_result);
     253         [ +  - ]:           1 :         add_coin(1 * CENT + input_fee, 2, expected_result);
     254         [ +  - ]:           1 :         CCoinControl coin_control;
     255                 :           1 :         coin_control.m_allow_other_inputs = true;
     256         [ +  - ]:           2 :         COutput select_coin = available_coins.All().at(1); // pre select 9 coin
     257         [ +  - ]:           1 :         coin_control.Select(select_coin.outpoint);
     258         [ +  - ]:           1 :         PreSelectedInputs selected_input;
     259         [ +  - ]:           1 :         selected_input.Insert(select_coin, coin_selection_params_bnb.m_subtract_fee_outputs);
     260   [ +  -  +  -  :           3 :         available_coins.Erase({(++available_coins.coins[OutputType::BECH32].begin())->outpoint});
             +  -  +  - ]
     261         [ +  - ]:           1 :         const auto result13 = SelectCoins(*wallet, available_coins, selected_input, 10 * CENT, coin_control, coin_selection_params_bnb);
     262   [ +  -  +  -  :           2 :         BOOST_CHECK(EquivalentResult(expected_result, *result13));
                   +  - ]
     263   [ +  -  +  - ]:           2 :     }
     264                 :             : 
     265                 :           1 :     {
     266                 :             :         // Test bnb max weight exceeded
     267                 :             :         // Inputs set [10, 9, 8, 5, 3, 1], Selection Target = 16 and coin 5 exceeding the max weight.
     268                 :             : 
     269   [ +  -  +  - ]:           1 :         std::unique_ptr<CWallet> wallet = NewWallet(m_node);
     270                 :             : 
     271         [ +  - ]:           1 :         CoinsResult available_coins;
     272         [ +  - ]:           1 :         add_coin(available_coins, *wallet, 10 * CENT, coin_selection_params_bnb.m_effective_feerate, 6 * 24, false, 0, true);
     273         [ +  - ]:           1 :         add_coin(available_coins, *wallet, 9 * CENT, coin_selection_params_bnb.m_effective_feerate, 6 * 24, false, 0, true);
     274         [ +  - ]:           1 :         add_coin(available_coins, *wallet, 8 * CENT, coin_selection_params_bnb.m_effective_feerate, 6 * 24, false, 0, true);
     275         [ +  - ]:           1 :         add_coin(available_coins, *wallet, 5 * CENT, coin_selection_params_bnb.m_effective_feerate, 6 * 24, false, 0, true, /*custom_size=*/MAX_STANDARD_TX_WEIGHT);
     276         [ +  - ]:           1 :         add_coin(available_coins, *wallet, 3 * CENT, coin_selection_params_bnb.m_effective_feerate, 6 * 24, false, 0, true);
     277         [ +  - ]:           1 :         add_coin(available_coins, *wallet, 1 * CENT, coin_selection_params_bnb.m_effective_feerate, 6 * 24, false, 0, true);
     278                 :             : 
     279                 :           1 :         CAmount selection_target = 16 * CENT;
     280                 :           0 :         const auto& no_res = SelectCoinsBnB(GroupCoins(available_coins.All(), /*subtract_fee_outputs*/true),
     281   [ +  -  +  -  :           2 :                                             selection_target, /*cost_of_change=*/0, MAX_STANDARD_TX_WEIGHT);
                   +  - ]
     282   [ +  -  +  -  :           2 :         BOOST_REQUIRE(!no_res);
                   +  - ]
     283   [ +  -  +  -  :           3 :         BOOST_CHECK(util::ErrorString(no_res).original.find("The inputs size exceeds the maximum weight") != std::string::npos);
             +  -  +  - ]
     284                 :             : 
     285                 :             :         // Now add same coin value with a good size and check that it gets selected
     286         [ +  - ]:           1 :         add_coin(available_coins, *wallet, 5 * CENT, coin_selection_params_bnb.m_effective_feerate, 6 * 24, false, 0, true);
     287   [ +  -  +  -  :           2 :         const auto& res = SelectCoinsBnB(GroupCoins(available_coins.All(), /*subtract_fee_outputs*/true), selection_target, /*cost_of_change=*/0);
                   +  - ]
     288                 :             : 
     289         [ +  - ]:           1 :         expected_result.Clear();
     290         [ +  - ]:           1 :         add_coin(8 * CENT, 2, expected_result);
     291         [ +  - ]:           1 :         add_coin(5 * CENT, 2, expected_result);
     292         [ +  - ]:           1 :         add_coin(3 * CENT, 2, expected_result);
     293   [ +  -  +  -  :           2 :         BOOST_CHECK(EquivalentResult(expected_result, *res));
                   +  - ]
     294         [ +  - ]:           2 :     }
     295                 :           1 : }
     296                 :             : 
     297   [ +  -  +  -  :           7 : BOOST_AUTO_TEST_CASE(bnb_sffo_restriction)
          +  -  +  -  -  
          +  +  -  +  -  
          +  -  +  -  +  
          -  +  -  -  +  
          +  -  +  -  +  
          -  +  -  +  -  
          +  -  -  +  +  
          -  +  -  +  -  
          +  -  +  -  +  
          -  +  -  -  +  
          +  -  +  -  +  
          -  +  -  +  -  
          +  -  -  +  +  
                      - ]
     298                 :             : {
     299                 :             :     // Verify the coin selection process does not produce a BnB solution when SFFO is enabled.
     300                 :             :     // This is currently problematic because it could require a change output. And BnB is specialized on changeless solutions.
     301         [ +  - ]:           1 :     std::unique_ptr<CWallet> wallet = NewWallet(m_node);
     302         [ +  - ]:           3 :     WITH_LOCK(wallet->cs_wallet, wallet->SetLastBlockProcessed(300, uint256{})); // set a high block so internal UTXOs are selectable
     303                 :             : 
     304                 :           1 :     FastRandomContext rand{};
     305         [ +  - ]:           1 :     CoinSelectionParams params{
     306                 :             :             rand,
     307                 :             :             /*change_output_size=*/ 31,  // unused value, p2wpkh output size (wallet default change type)
     308                 :             :             /*change_spend_size=*/ 68,   // unused value, p2wpkh input size (high-r signature)
     309                 :             :             /*min_change_target=*/ 0,    // dummy, set later
     310                 :           1 :             /*effective_feerate=*/ CFeeRate(3000),
     311                 :           1 :             /*long_term_feerate=*/ CFeeRate(1000),
     312                 :           1 :             /*discard_feerate=*/ CFeeRate(1000),
     313                 :             :             /*tx_noinputs_size=*/ 0,
     314                 :             :             /*avoid_partial=*/ false,
     315         [ +  - ]:           1 :     };
     316                 :           1 :     params.m_subtract_fee_outputs = true;
     317         [ +  - ]:           1 :     params.m_change_fee = params.m_effective_feerate.GetFee(params.change_output_size);
     318         [ +  - ]:           1 :     params.m_cost_of_change = params.m_discard_feerate.GetFee(params.change_spend_size) + params.m_change_fee;
     319                 :           1 :     params.m_min_change_target = params.m_cost_of_change + 1;
     320                 :             :     // Add spendable coin at the BnB selection upper bound
     321         [ +  - ]:           1 :     CoinsResult available_coins;
     322         [ +  - ]:           1 :     add_coin(available_coins, *wallet, COIN + params.m_cost_of_change, /*feerate=*/params.m_effective_feerate, /*nAge=*/6, /*fIsFromMe=*/true, /*nInput=*/0, /*spendable=*/true);
     323         [ +  - ]:           1 :     add_coin(available_coins, *wallet, 0.5 * COIN + params.m_cost_of_change, /*feerate=*/params.m_effective_feerate, /*nAge=*/6, /*fIsFromMe=*/true, /*nInput=*/0, /*spendable=*/true);
     324         [ +  - ]:           1 :     add_coin(available_coins, *wallet, 0.5 * COIN, /*feerate=*/params.m_effective_feerate, /*nAge=*/6, /*fIsFromMe=*/true, /*nInput=*/0, /*spendable=*/true);
     325                 :             :     // Knapsack will only find a changeless solution on an exact match to the satoshi, SRD doesn’t look for changeless
     326                 :             :     // If BnB were run, it would produce a single input solution with the best waste score
     327   [ +  -  +  -  :           4 :     auto result = WITH_LOCK(wallet->cs_wallet, return SelectCoins(*wallet, available_coins, /*pre_set_inputs=*/{}, COIN, /*coin_control=*/{}, params));
                   +  - ]
     328   [ +  -  +  -  :           2 :     BOOST_CHECK(result.has_value());
                   +  - ]
     329   [ +  -  +  - ]:           1 :     BOOST_CHECK_NE(result->GetAlgo(), SelectionAlgorithm::BNB);
     330   [ +  -  +  -  :           2 :     BOOST_CHECK(result->GetInputSet().size() == 2);
             +  -  +  - ]
     331                 :             :     // We have only considered BnB, SRD, and Knapsack. Test needs to be reevaluated if new algo is added
     332   [ +  -  +  -  :           3 :     BOOST_CHECK(result->GetAlgo() == SelectionAlgorithm::SRD || result->GetAlgo() == SelectionAlgorithm::KNAPSACK);
             +  -  +  - ]
     333         [ +  - ]:           2 : }
     334                 :             : 
     335   [ +  -  +  -  :           7 : BOOST_AUTO_TEST_CASE(knapsack_solver_test)
          +  -  +  -  -  
          +  +  -  +  -  
          +  -  +  -  +  
          -  +  -  -  +  
          +  -  +  -  +  
          -  +  -  +  -  
          +  -  -  +  +  
          -  +  -  +  -  
          +  -  +  -  +  
          -  +  -  -  +  
          +  -  +  -  +  
          -  +  -  +  -  
          +  -  -  +  +  
                      - ]
     336                 :             : {
     337                 :           1 :     FastRandomContext rand{};
     338                 :        5601 :     const auto temp1{[&rand](std::vector<OutputGroup>& g, const CAmount& v, CAmount c) { return KnapsackSolver(g, v, c, rand); }};
     339                 :           1 :     const auto KnapsackSolver{temp1};
     340   [ +  -  +  - ]:           1 :     std::unique_ptr<CWallet> wallet = NewWallet(m_node);
     341                 :             : 
     342                 :           1 :     CoinsResult available_coins;
     343                 :             : 
     344                 :             :     // test multiple times to allow for differences in the shuffle order
     345         [ +  + ]:         101 :     for (int i = 0; i < RUN_TESTS; i++)
     346                 :             :     {
     347         [ +  - ]:         100 :         available_coins.Clear();
     348                 :             : 
     349                 :             :         // with an empty wallet we can't even pay one cent
     350   [ +  -  +  -  :         200 :         BOOST_CHECK(!KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_standard), 1 * CENT, CENT));
          +  -  +  -  +  
                      - ]
     351                 :             : 
     352         [ +  - ]:         100 :         add_coin(available_coins, *wallet, 1*CENT, CFeeRate(0), 4);        // add a new 1 cent coin
     353                 :             : 
     354                 :             :         // with a new 1 cent coin, we still can't find a mature 1 cent
     355   [ +  -  +  -  :         200 :         BOOST_CHECK(!KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_standard), 1 * CENT, CENT));
          +  -  +  -  +  
                      - ]
     356                 :             : 
     357                 :             :         // but we can find a new 1 cent
     358   [ +  -  +  - ]:         100 :         const auto result1 = KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_confirmed), 1 * CENT, CENT);
     359   [ +  -  +  -  :         200 :         BOOST_CHECK(result1);
                   +  - ]
     360   [ +  -  +  -  :         100 :         BOOST_CHECK_EQUAL(result1->GetSelectedValue(), 1 * CENT);
                   +  - ]
     361                 :             : 
     362         [ +  - ]:         100 :         add_coin(available_coins, *wallet, 2*CENT);           // add a mature 2 cent coin
     363                 :             : 
     364                 :             :         // we can't make 3 cents of mature coins
     365   [ +  -  +  -  :         200 :         BOOST_CHECK(!KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_standard), 3 * CENT, CENT));
          +  -  +  -  +  
                      - ]
     366                 :             : 
     367                 :             :         // we can make 3 cents of new coins
     368   [ +  -  +  - ]:         100 :         const auto result2 = KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_confirmed), 3 * CENT, CENT);
     369   [ +  -  +  -  :         200 :         BOOST_CHECK(result2);
                   +  - ]
     370   [ +  -  +  -  :         100 :         BOOST_CHECK_EQUAL(result2->GetSelectedValue(), 3 * CENT);
                   +  - ]
     371                 :             : 
     372         [ +  - ]:         100 :         add_coin(available_coins, *wallet, 5*CENT);           // add a mature 5 cent coin,
     373         [ +  - ]:         100 :         add_coin(available_coins, *wallet, 10*CENT, CFeeRate(0), 3, true); // a new 10 cent coin sent from one of our own addresses
     374         [ +  - ]:         100 :         add_coin(available_coins, *wallet, 20*CENT);          // and a mature 20 cent coin
     375                 :             : 
     376                 :             :         // now we have new: 1+10=11 (of which 10 was self-sent), and mature: 2+5+20=27.  total = 38
     377                 :             : 
     378                 :             :         // we can't make 38 cents only if we disallow new coins:
     379   [ +  -  +  -  :         200 :         BOOST_CHECK(!KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_standard), 38 * CENT, CENT));
          +  -  +  -  +  
                      - ]
     380                 :             :         // we can't even make 37 cents if we don't allow new coins even if they're from us
     381   [ +  -  +  -  :         200 :         BOOST_CHECK(!KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_standard_extra), 38 * CENT, CENT));
          +  -  +  -  +  
                      - ]
     382                 :             :         // but we can make 37 cents if we accept new coins from ourself
     383   [ +  -  +  - ]:         100 :         const auto result3 = KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_standard), 37 * CENT, CENT);
     384   [ +  -  +  -  :         200 :         BOOST_CHECK(result3);
                   +  - ]
     385   [ +  -  +  -  :         100 :         BOOST_CHECK_EQUAL(result3->GetSelectedValue(), 37 * CENT);
                   +  - ]
     386                 :             :         // and we can make 38 cents if we accept all new coins
     387   [ +  -  +  - ]:         100 :         const auto result4 = KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_confirmed), 38 * CENT, CENT);
     388   [ +  -  +  -  :         200 :         BOOST_CHECK(result4);
                   +  - ]
     389   [ +  -  +  -  :         100 :         BOOST_CHECK_EQUAL(result4->GetSelectedValue(), 38 * CENT);
                   +  - ]
     390                 :             : 
     391                 :             :         // try making 34 cents from 1,2,5,10,20 - we can't do it exactly
     392   [ +  -  +  - ]:         100 :         const auto result5 = KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_confirmed), 34 * CENT, CENT);
     393   [ +  -  +  -  :         200 :         BOOST_CHECK(result5);
                   +  - ]
     394   [ +  -  +  -  :         100 :         BOOST_CHECK_EQUAL(result5->GetSelectedValue(), 35 * CENT);       // but 35 cents is closest
                   +  - ]
     395   [ +  -  +  -  :         100 :         BOOST_CHECK_EQUAL(result5->GetInputSet().size(), 3U);     // the best should be 20+10+5.  it's incredibly unlikely the 1 or 2 got included (but possible)
                   +  - ]
     396                 :             : 
     397                 :             :         // when we try making 7 cents, the smaller coins (1,2,5) are enough.  We should see just 2+5
     398   [ +  -  +  - ]:         100 :         const auto result6 = KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_confirmed), 7 * CENT, CENT);
     399   [ +  -  +  -  :         200 :         BOOST_CHECK(result6);
                   +  - ]
     400   [ +  -  +  -  :         100 :         BOOST_CHECK_EQUAL(result6->GetSelectedValue(), 7 * CENT);
                   +  - ]
     401   [ +  -  +  -  :         100 :         BOOST_CHECK_EQUAL(result6->GetInputSet().size(), 2U);
                   +  - ]
     402                 :             : 
     403                 :             :         // when we try making 8 cents, the smaller coins (1,2,5) are exactly enough.
     404   [ +  -  +  - ]:         100 :         const auto result7 = KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_confirmed), 8 * CENT, CENT);
     405   [ +  -  +  -  :         200 :         BOOST_CHECK(result7);
                   +  - ]
     406   [ +  -  +  -  :         200 :         BOOST_CHECK(result7->GetSelectedValue() == 8 * CENT);
             +  -  +  - ]
     407   [ +  -  +  -  :         100 :         BOOST_CHECK_EQUAL(result7->GetInputSet().size(), 3U);
                   +  - ]
     408                 :             : 
     409                 :             :         // when we try making 9 cents, no subset of smaller coins is enough, and we get the next bigger coin (10)
     410   [ +  -  +  - ]:         100 :         const auto result8 = KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_confirmed), 9 * CENT, CENT);
     411   [ +  -  +  -  :         200 :         BOOST_CHECK(result8);
                   +  - ]
     412   [ +  -  +  -  :         100 :         BOOST_CHECK_EQUAL(result8->GetSelectedValue(), 10 * CENT);
                   +  - ]
     413   [ +  -  +  -  :         100 :         BOOST_CHECK_EQUAL(result8->GetInputSet().size(), 1U);
                   +  - ]
     414                 :             : 
     415                 :             :         // now clear out the wallet and start again to test choosing between subsets of smaller coins and the next biggest coin
     416         [ +  - ]:         100 :         available_coins.Clear();
     417                 :             : 
     418         [ +  - ]:         100 :         add_coin(available_coins, *wallet,  6*CENT);
     419         [ +  - ]:         100 :         add_coin(available_coins, *wallet,  7*CENT);
     420         [ +  - ]:         100 :         add_coin(available_coins, *wallet,  8*CENT);
     421         [ +  - ]:         100 :         add_coin(available_coins, *wallet, 20*CENT);
     422         [ +  - ]:         100 :         add_coin(available_coins, *wallet, 30*CENT); // now we have 6+7+8+20+30 = 71 cents total
     423                 :             : 
     424                 :             :         // check that we have 71 and not 72
     425   [ +  -  +  - ]:         100 :         const auto result9 = KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_confirmed), 71 * CENT, CENT);
     426   [ +  -  +  -  :         200 :         BOOST_CHECK(result9);
                   +  - ]
     427   [ +  -  +  -  :         200 :         BOOST_CHECK(!KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_confirmed), 72 * CENT, CENT));
          +  -  +  -  +  
                      - ]
     428                 :             : 
     429                 :             :         // now try making 16 cents.  the best smaller coins can do is 6+7+8 = 21; not as good at the next biggest coin, 20
     430   [ +  -  +  - ]:         100 :         const auto result10 = KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_confirmed), 16 * CENT, CENT);
     431   [ +  -  +  -  :         200 :         BOOST_CHECK(result10);
                   +  - ]
     432   [ +  -  +  -  :         100 :         BOOST_CHECK_EQUAL(result10->GetSelectedValue(), 20 * CENT); // we should get 20 in one coin
                   +  - ]
     433   [ +  -  +  -  :         100 :         BOOST_CHECK_EQUAL(result10->GetInputSet().size(), 1U);
                   +  - ]
     434                 :             : 
     435         [ +  - ]:         100 :         add_coin(available_coins, *wallet,  5*CENT); // now we have 5+6+7+8+20+30 = 75 cents total
     436                 :             : 
     437                 :             :         // now if we try making 16 cents again, the smaller coins can make 5+6+7 = 18 cents, better than the next biggest coin, 20
     438   [ +  -  +  - ]:         100 :         const auto result11 = KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_confirmed), 16 * CENT, CENT);
     439   [ +  -  +  -  :         200 :         BOOST_CHECK(result11);
                   +  - ]
     440   [ +  -  +  -  :         100 :         BOOST_CHECK_EQUAL(result11->GetSelectedValue(), 18 * CENT); // we should get 18 in 3 coins
                   +  - ]
     441   [ +  -  +  -  :         100 :         BOOST_CHECK_EQUAL(result11->GetInputSet().size(), 3U);
                   +  - ]
     442                 :             : 
     443         [ +  - ]:         100 :         add_coin(available_coins, *wallet,  18*CENT); // now we have 5+6+7+8+18+20+30
     444                 :             : 
     445                 :             :         // and now if we try making 16 cents again, the smaller coins can make 5+6+7 = 18 cents, the same as the next biggest coin, 18
     446   [ +  -  +  - ]:         100 :         const auto result12 = KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_confirmed), 16 * CENT, CENT);
     447   [ +  -  +  -  :         200 :         BOOST_CHECK(result12);
                   +  - ]
     448   [ +  -  +  -  :         100 :         BOOST_CHECK_EQUAL(result12->GetSelectedValue(), 18 * CENT);  // we should get 18 in 1 coin
                   +  - ]
     449   [ +  -  +  -  :         100 :         BOOST_CHECK_EQUAL(result12->GetInputSet().size(), 1U); // because in the event of a tie, the biggest coin wins
                   +  - ]
     450                 :             : 
     451                 :             :         // now try making 11 cents.  we should get 5+6
     452   [ +  -  +  - ]:         100 :         const auto result13 = KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_confirmed), 11 * CENT, CENT);
     453   [ +  -  +  -  :         200 :         BOOST_CHECK(result13);
                   +  - ]
     454   [ +  -  +  -  :         100 :         BOOST_CHECK_EQUAL(result13->GetSelectedValue(), 11 * CENT);
                   +  - ]
     455   [ +  -  +  -  :         100 :         BOOST_CHECK_EQUAL(result13->GetInputSet().size(), 2U);
                   +  - ]
     456                 :             : 
     457                 :             :         // check that the smallest bigger coin is used
     458         [ +  - ]:         100 :         add_coin(available_coins, *wallet,  1*COIN);
     459         [ +  - ]:         100 :         add_coin(available_coins, *wallet,  2*COIN);
     460         [ +  - ]:         100 :         add_coin(available_coins, *wallet,  3*COIN);
     461         [ +  - ]:         100 :         add_coin(available_coins, *wallet,  4*COIN); // now we have 5+6+7+8+18+20+30+100+200+300+400 = 1094 cents
     462   [ +  -  +  - ]:         100 :         const auto result14 = KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_confirmed), 95 * CENT, CENT);
     463   [ +  -  +  -  :         200 :         BOOST_CHECK(result14);
                   +  - ]
     464   [ +  -  +  -  :         100 :         BOOST_CHECK_EQUAL(result14->GetSelectedValue(), 1 * COIN);  // we should get 1 BTC in 1 coin
                   +  - ]
     465   [ +  -  +  -  :         100 :         BOOST_CHECK_EQUAL(result14->GetInputSet().size(), 1U);
                   +  - ]
     466                 :             : 
     467   [ +  -  +  - ]:         100 :         const auto result15 = KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_confirmed), 195 * CENT, CENT);
     468   [ +  -  +  -  :         200 :         BOOST_CHECK(result15);
                   +  - ]
     469   [ +  -  +  -  :         100 :         BOOST_CHECK_EQUAL(result15->GetSelectedValue(), 2 * COIN);  // we should get 2 BTC in 1 coin
                   +  - ]
     470   [ +  -  +  -  :         100 :         BOOST_CHECK_EQUAL(result15->GetInputSet().size(), 1U);
                   +  - ]
     471                 :             : 
     472                 :             :         // empty the wallet and start again, now with fractions of a cent, to test small change avoidance
     473                 :             : 
     474         [ +  - ]:         100 :         available_coins.Clear();
     475         [ +  - ]:         100 :         add_coin(available_coins, *wallet, CENT * 1 / 10);
     476         [ +  - ]:         100 :         add_coin(available_coins, *wallet, CENT * 2 / 10);
     477         [ +  - ]:         100 :         add_coin(available_coins, *wallet, CENT * 3 / 10);
     478         [ +  - ]:         100 :         add_coin(available_coins, *wallet, CENT * 4 / 10);
     479         [ +  - ]:         100 :         add_coin(available_coins, *wallet, CENT * 5 / 10);
     480                 :             : 
     481                 :             :         // try making 1 * CENT from the 1.5 * CENT
     482                 :             :         // we'll get change smaller than CENT whatever happens, so can expect CENT exactly
     483   [ +  -  +  - ]:         100 :         const auto result16 = KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_confirmed), CENT, CENT);
     484   [ +  -  +  -  :         200 :         BOOST_CHECK(result16);
                   +  - ]
     485   [ +  -  +  -  :         100 :         BOOST_CHECK_EQUAL(result16->GetSelectedValue(), CENT);
                   +  - ]
     486                 :             : 
     487                 :             :         // but if we add a bigger coin, small change is avoided
     488         [ +  - ]:         100 :         add_coin(available_coins, *wallet, 1111*CENT);
     489                 :             : 
     490                 :             :         // try making 1 from 0.1 + 0.2 + 0.3 + 0.4 + 0.5 + 1111 = 1112.5
     491   [ +  -  +  - ]:         100 :         const auto result17 = KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_confirmed), 1 * CENT, CENT);
     492   [ +  -  +  -  :         200 :         BOOST_CHECK(result17);
                   +  - ]
     493   [ +  -  +  -  :         100 :         BOOST_CHECK_EQUAL(result17->GetSelectedValue(), 1 * CENT); // we should get the exact amount
                   +  - ]
     494                 :             : 
     495                 :             :         // if we add more small coins:
     496         [ +  - ]:         100 :         add_coin(available_coins, *wallet, CENT * 6 / 10);
     497         [ +  - ]:         100 :         add_coin(available_coins, *wallet, CENT * 7 / 10);
     498                 :             : 
     499                 :             :         // and try again to make 1.0 * CENT
     500   [ +  -  +  - ]:         100 :         const auto result18 = KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_confirmed), 1 * CENT, CENT);
     501   [ +  -  +  -  :         200 :         BOOST_CHECK(result18);
                   +  - ]
     502   [ +  -  +  -  :         100 :         BOOST_CHECK_EQUAL(result18->GetSelectedValue(), 1 * CENT); // we should get the exact amount
                   +  - ]
     503                 :             : 
     504                 :             :         // run the 'mtgox' test (see https://blockexplorer.com/tx/29a3efd3ef04f9153d47a990bd7b048a4b2d213daaa5fb8ed670fb85f13bdbcf)
     505                 :             :         // they tried to consolidate 10 50k coins into one 500k coin, and ended up with 50k in change
     506         [ +  - ]:         100 :         available_coins.Clear();
     507         [ +  + ]:        2100 :         for (int j = 0; j < 20; j++)
     508         [ +  - ]:        2000 :             add_coin(available_coins, *wallet, 50000 * COIN);
     509                 :             : 
     510   [ +  -  +  - ]:         100 :         const auto result19 = KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_confirmed), 500000 * COIN, CENT);
     511   [ +  -  +  -  :         200 :         BOOST_CHECK(result19);
                   +  - ]
     512   [ +  -  +  -  :         100 :         BOOST_CHECK_EQUAL(result19->GetSelectedValue(), 500000 * COIN); // we should get the exact amount
                   +  - ]
     513   [ +  -  +  -  :         100 :         BOOST_CHECK_EQUAL(result19->GetInputSet().size(), 10U); // in ten coins
                   +  - ]
     514                 :             : 
     515                 :             :         // if there's not enough in the smaller coins to make at least 1 * CENT change (0.5+0.6+0.7 < 1.0+1.0),
     516                 :             :         // we need to try finding an exact subset anyway
     517                 :             : 
     518                 :             :         // sometimes it will fail, and so we use the next biggest coin:
     519         [ +  - ]:         100 :         available_coins.Clear();
     520         [ +  - ]:         100 :         add_coin(available_coins, *wallet, CENT * 5 / 10);
     521         [ +  - ]:         100 :         add_coin(available_coins, *wallet, CENT * 6 / 10);
     522         [ +  - ]:         100 :         add_coin(available_coins, *wallet, CENT * 7 / 10);
     523         [ +  - ]:         100 :         add_coin(available_coins, *wallet, 1111 * CENT);
     524   [ +  -  +  - ]:         100 :         const auto result20 = KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_confirmed), 1 * CENT, CENT);
     525   [ +  -  +  -  :         200 :         BOOST_CHECK(result20);
                   +  - ]
     526   [ +  -  +  -  :         100 :         BOOST_CHECK_EQUAL(result20->GetSelectedValue(), 1111 * CENT); // we get the bigger coin
                   +  - ]
     527   [ +  -  +  -  :         100 :         BOOST_CHECK_EQUAL(result20->GetInputSet().size(), 1U);
                   +  - ]
     528                 :             : 
     529                 :             :         // but sometimes it's possible, and we use an exact subset (0.4 + 0.6 = 1.0)
     530         [ +  - ]:         100 :         available_coins.Clear();
     531         [ +  - ]:         100 :         add_coin(available_coins, *wallet, CENT * 4 / 10);
     532         [ +  - ]:         100 :         add_coin(available_coins, *wallet, CENT * 6 / 10);
     533         [ +  - ]:         100 :         add_coin(available_coins, *wallet, CENT * 8 / 10);
     534         [ +  - ]:         100 :         add_coin(available_coins, *wallet, 1111 * CENT);
     535   [ +  -  +  - ]:         100 :         const auto result21 = KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_confirmed), CENT, CENT);
     536   [ +  -  +  -  :         200 :         BOOST_CHECK(result21);
                   +  - ]
     537   [ +  -  +  -  :         100 :         BOOST_CHECK_EQUAL(result21->GetSelectedValue(), CENT);   // we should get the exact amount
                   +  - ]
     538   [ +  -  +  -  :         100 :         BOOST_CHECK_EQUAL(result21->GetInputSet().size(), 2U); // in two coins 0.4+0.6
                   +  - ]
     539                 :             : 
     540                 :             :         // test avoiding small change
     541         [ +  - ]:         100 :         available_coins.Clear();
     542         [ +  - ]:         100 :         add_coin(available_coins, *wallet, CENT * 5 / 100);
     543         [ +  - ]:         100 :         add_coin(available_coins, *wallet, CENT * 1);
     544         [ +  - ]:         100 :         add_coin(available_coins, *wallet, CENT * 100);
     545                 :             : 
     546                 :             :         // trying to make 100.01 from these three coins
     547   [ +  -  +  - ]:         100 :         const auto result22 = KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_confirmed), CENT * 10001 / 100, CENT);
     548   [ +  -  +  -  :         200 :         BOOST_CHECK(result22);
                   +  - ]
     549   [ +  -  +  -  :         100 :         BOOST_CHECK_EQUAL(result22->GetSelectedValue(), CENT * 10105 / 100); // we should get all coins
                   +  - ]
     550   [ +  -  +  -  :         100 :         BOOST_CHECK_EQUAL(result22->GetInputSet().size(), 3U);
                   +  - ]
     551                 :             : 
     552                 :             :         // but if we try to make 99.9, we should take the bigger of the two small coins to avoid small change
     553   [ +  -  +  - ]:         100 :         const auto result23 = KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_confirmed), CENT * 9990 / 100, CENT);
     554   [ +  -  +  -  :         200 :         BOOST_CHECK(result23);
                   +  - ]
     555   [ +  -  +  -  :         100 :         BOOST_CHECK_EQUAL(result23->GetSelectedValue(), 101 * CENT);
                   +  - ]
     556   [ +  -  +  -  :         100 :         BOOST_CHECK_EQUAL(result23->GetInputSet().size(), 2U);
                   +  - ]
     557                 :         100 :     }
     558                 :             : 
     559                 :             :     // test with many inputs
     560         [ +  + ]:           6 :     for (CAmount amt=1500; amt < COIN; amt*=10) {
     561         [ +  - ]:           5 :         available_coins.Clear();
     562                 :             :         // Create 676 inputs (=  (old MAX_STANDARD_TX_SIZE == 100000)  / 148 bytes per input)
     563         [ +  + ]:        3385 :         for (uint16_t j = 0; j < 676; j++)
     564         [ +  - ]:        3380 :             add_coin(available_coins, *wallet, amt);
     565                 :             : 
     566                 :             :         // We only create the wallet once to save time, but we still run the coin selection RUN_TESTS times.
     567         [ +  + ]:         505 :         for (int i = 0; i < RUN_TESTS; i++) {
     568   [ +  -  +  - ]:         500 :             const auto result24 = KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_confirmed), 2000, CENT);
     569   [ +  -  +  -  :        1000 :             BOOST_CHECK(result24);
                   +  + ]
     570                 :             : 
     571         [ +  + ]:         500 :             if (amt - 2000 < CENT) {
     572                 :             :                 // needs more than one input:
     573                 :         300 :                 uint16_t returnSize = std::ceil((2000.0 + CENT)/amt);
     574                 :         300 :                 CAmount returnValue = amt * returnSize;
     575   [ +  -  +  -  :         300 :                 BOOST_CHECK_EQUAL(result24->GetSelectedValue(), returnValue);
                   +  - ]
     576   [ +  -  +  -  :         300 :                 BOOST_CHECK_EQUAL(result24->GetInputSet().size(), returnSize);
                   +  - ]
     577                 :             :             } else {
     578                 :             :                 // one input is sufficient:
     579   [ +  -  +  -  :         200 :                 BOOST_CHECK_EQUAL(result24->GetSelectedValue(), amt);
                   +  - ]
     580   [ +  -  +  -  :         500 :                 BOOST_CHECK_EQUAL(result24->GetInputSet().size(), 1U);
                   +  - ]
     581                 :             :             }
     582                 :         500 :         }
     583                 :             :     }
     584                 :             : 
     585                 :             :     // test randomness
     586                 :           1 :     {
     587         [ +  - ]:           1 :         available_coins.Clear();
     588         [ +  + ]:         101 :         for (int i2 = 0; i2 < 100; i2++)
     589         [ +  - ]:         100 :             add_coin(available_coins, *wallet, COIN);
     590                 :             : 
     591                 :             :         // Again, we only create the wallet once to save time, but we still run the coin selection RUN_TESTS times.
     592         [ +  + ]:         101 :         for (int i = 0; i < RUN_TESTS; i++) {
     593                 :             :             // picking 50 from 100 coins doesn't depend on the shuffle,
     594                 :             :             // but does depend on randomness in the stochastic approximation code
     595   [ +  -  +  -  :         100 :             const auto result25 = KnapsackSolver(GroupCoins(available_coins.All()), 50 * COIN, CENT);
                   +  - ]
     596   [ +  -  +  -  :         200 :             BOOST_CHECK(result25);
                   +  - ]
     597   [ +  -  +  -  :         100 :             const auto result26 = KnapsackSolver(GroupCoins(available_coins.All()), 50 * COIN, CENT);
                   +  - ]
     598   [ +  -  +  -  :         200 :             BOOST_CHECK(result26);
                   +  - ]
     599   [ +  -  +  -  :         200 :             BOOST_CHECK(!EqualResult(*result25, *result26));
                   +  - ]
     600                 :             : 
     601                 :         100 :             int fails = 0;
     602         [ +  + ]:         600 :             for (int j = 0; j < RANDOM_REPEATS; j++)
     603                 :             :             {
     604                 :             :                 // Test that the KnapsackSolver selects randomly from equivalent coins (same value and same input size).
     605                 :             :                 // When choosing 1 from 100 identical coins, 1% of the time, this test will choose the same coin twice
     606                 :             :                 // which will cause it to fail.
     607                 :             :                 // To avoid that issue, run the test RANDOM_REPEATS times and only complain if all of them fail
     608   [ +  -  +  -  :         500 :                 const auto result27 = KnapsackSolver(GroupCoins(available_coins.All()), COIN, CENT);
                   +  - ]
     609   [ +  -  +  -  :        1000 :                 BOOST_CHECK(result27);
                   +  - ]
     610   [ +  -  +  -  :         500 :                 const auto result28 = KnapsackSolver(GroupCoins(available_coins.All()), COIN, CENT);
                   +  - ]
     611   [ +  -  +  -  :        1000 :                 BOOST_CHECK(result28);
                   +  - ]
     612   [ +  -  +  + ]:         500 :                 if (EqualResult(*result27, *result28))
     613                 :           7 :                     fails++;
     614                 :         500 :             }
     615   [ +  -  +  - ]:         100 :             BOOST_CHECK_NE(fails, RANDOM_REPEATS);
     616                 :         100 :         }
     617                 :             : 
     618                 :             :         // add 75 cents in small change.  not enough to make 90 cents,
     619                 :             :         // then try making 90 cents.  there are multiple competing "smallest bigger" coins,
     620                 :             :         // one of which should be picked at random
     621         [ +  - ]:           1 :         add_coin(available_coins, *wallet, 5 * CENT);
     622         [ +  - ]:           1 :         add_coin(available_coins, *wallet, 10 * CENT);
     623         [ +  - ]:           1 :         add_coin(available_coins, *wallet, 15 * CENT);
     624         [ +  - ]:           1 :         add_coin(available_coins, *wallet, 20 * CENT);
     625         [ +  - ]:           1 :         add_coin(available_coins, *wallet, 25 * CENT);
     626                 :             : 
     627         [ +  + ]:         101 :         for (int i = 0; i < RUN_TESTS; i++) {
     628                 :         100 :             int fails = 0;
     629         [ +  + ]:         600 :             for (int j = 0; j < RANDOM_REPEATS; j++)
     630                 :             :             {
     631   [ +  -  +  -  :         500 :                 const auto result29 = KnapsackSolver(GroupCoins(available_coins.All()), 90 * CENT, CENT);
                   +  - ]
     632   [ +  -  +  -  :        1000 :                 BOOST_CHECK(result29);
                   +  - ]
     633   [ +  -  +  -  :         500 :                 const auto result30 = KnapsackSolver(GroupCoins(available_coins.All()), 90 * CENT, CENT);
                   +  - ]
     634   [ +  -  +  -  :        1000 :                 BOOST_CHECK(result30);
                   +  - ]
     635   [ +  -  +  + ]:         500 :                 if (EqualResult(*result29, *result30))
     636                 :           3 :                     fails++;
     637                 :         500 :             }
     638   [ +  -  +  - ]:         100 :             BOOST_CHECK_NE(fails, RANDOM_REPEATS);
     639                 :             :         }
     640                 :             :     }
     641         [ +  - ]:           2 : }
     642                 :             : 
     643   [ +  -  +  -  :           7 : BOOST_AUTO_TEST_CASE(ApproximateBestSubset)
          +  -  +  -  -  
          +  +  -  +  -  
          +  -  +  -  +  
          -  +  -  -  +  
          +  -  +  -  +  
          -  +  -  +  -  
          +  -  -  +  +  
          -  +  -  +  -  
          +  -  +  -  +  
          -  +  -  -  +  
          +  -  +  -  +  
          -  +  -  +  -  
          +  -  -  +  +  
                      - ]
     644                 :             : {
     645                 :           1 :     FastRandomContext rand{};
     646   [ +  -  +  - ]:           1 :     std::unique_ptr<CWallet> wallet = NewWallet(m_node);
     647                 :             : 
     648                 :           1 :     CoinsResult available_coins;
     649                 :             : 
     650                 :             :     // Test vValue sort order
     651         [ +  + ]:        1001 :     for (int i = 0; i < 1000; i++)
     652         [ +  - ]:        1000 :         add_coin(available_coins, *wallet, 1000 * COIN);
     653         [ +  - ]:           1 :     add_coin(available_coins, *wallet, 3 * COIN);
     654                 :             : 
     655   [ +  -  +  - ]:           1 :     const auto result = KnapsackSolver(KnapsackGroupOutputs(available_coins, *wallet, filter_standard), 1003 * COIN, CENT, rand);
     656   [ +  -  +  -  :           2 :     BOOST_CHECK(result);
                   +  - ]
     657   [ +  -  +  -  :           1 :     BOOST_CHECK_EQUAL(result->GetSelectedValue(), 1003 * COIN);
                   +  - ]
     658   [ +  -  +  -  :           1 :     BOOST_CHECK_EQUAL(result->GetInputSet().size(), 2U);
                   +  - ]
     659         [ +  - ]:           2 : }
     660                 :             : 
     661                 :             : // Tests that with the ideal conditions, the coin selector will always be able to find a solution that can pay the target value
     662   [ +  -  +  -  :           7 : BOOST_AUTO_TEST_CASE(SelectCoins_test)
          +  -  +  -  -  
          +  +  -  +  -  
          +  -  +  -  +  
          -  +  -  -  +  
          +  -  +  -  +  
          -  +  -  +  -  
          +  -  -  +  +  
          -  +  -  +  -  
          +  -  +  -  +  
          -  +  -  -  +  
          +  -  +  -  +  
          -  +  -  +  -  
          +  -  -  +  +  
                      - ]
     663                 :             : {
     664         [ +  - ]:           1 :     std::unique_ptr<CWallet> wallet = NewWallet(m_node);
     665         [ +  - ]:           1 :     LOCK(wallet->cs_wallet); // Every 'SelectCoins' call requires it
     666                 :             : 
     667                 :             :     // Random generator stuff
     668                 :           1 :     std::default_random_engine generator;
     669                 :           1 :     std::exponential_distribution<double> distribution (100);
     670                 :           1 :     FastRandomContext rand;
     671                 :             : 
     672                 :             :     // Run this test 100 times
     673         [ +  + ]:         101 :     for (int i = 0; i < 100; ++i)
     674                 :             :     {
     675                 :         100 :         CoinsResult available_coins;
     676                 :         100 :         CAmount balance{0};
     677                 :             : 
     678                 :             :         // Make a wallet with 1000 exponentially distributed random inputs
     679         [ +  + ]:      100100 :         for (int j = 0; j < 1000; ++j)
     680                 :             :         {
     681                 :      100000 :             CAmount val = distribution(generator)*10000000;
     682         [ +  - ]:      100000 :             add_coin(available_coins, *wallet, val);
     683                 :      100000 :             balance += val;
     684                 :             :         }
     685                 :             : 
     686                 :             :         // Generate a random fee rate in the range of 100 - 400
     687                 :         100 :         CFeeRate rate(rand.randrange(300) + 100);
     688                 :             : 
     689                 :             :         // Generate a random target value between 1000 and wallet balance
     690                 :         100 :         CAmount target = rand.randrange(balance - 1000) + 1000;
     691                 :             : 
     692                 :             :         // Perform selection
     693         [ +  - ]:         100 :         CoinSelectionParams cs_params{
     694                 :             :             rand,
     695                 :             :             /*change_output_size=*/ 34,
     696                 :             :             /*change_spend_size=*/ 148,
     697                 :             :             /*min_change_target=*/ CENT,
     698                 :         100 :             /*effective_feerate=*/ CFeeRate(0),
     699                 :         100 :             /*long_term_feerate=*/ CFeeRate(0),
     700                 :         100 :             /*discard_feerate=*/ CFeeRate(0),
     701                 :             :             /*tx_noinputs_size=*/ 0,
     702                 :             :             /*avoid_partial=*/ false,
     703         [ +  - ]:         100 :         };
     704                 :         100 :         cs_params.m_cost_of_change = 1;
     705                 :         100 :         cs_params.min_viable_change = 1;
     706         [ +  - ]:         100 :         CCoinControl cc;
     707                 :           0 :         const auto result = SelectCoins(*wallet, available_coins, /*pre_set_inputs=*/{}, target, cc, cs_params);
     708   [ +  -  +  -  :         200 :         BOOST_CHECK(result);
                   +  - ]
     709   [ +  -  +  -  :         100 :         BOOST_CHECK_GE(result->GetSelectedValue(), target);
                   +  - ]
     710                 :         100 :     }
     711   [ +  -  +  -  :         103 : }
                   +  - ]
     712                 :             : 
     713   [ +  -  +  -  :           7 : BOOST_AUTO_TEST_CASE(waste_test)
          +  -  +  -  -  
          +  +  -  +  -  
          +  -  +  -  +  
          -  +  -  -  +  
          +  -  +  -  +  
          -  +  -  +  -  
          +  -  -  +  +  
          -  +  -  +  -  
          +  -  +  -  +  
          -  +  -  -  +  
          +  -  +  -  +  
          -  +  -  +  -  
          +  -  -  +  +  
                      - ]
     714                 :             : {
     715                 :           1 :     const CAmount fee{100};
     716                 :           1 :     const CAmount min_viable_change{300};
     717                 :           1 :     const CAmount change_cost{125};
     718                 :           1 :     const CAmount change_fee{30};
     719                 :           1 :     const CAmount fee_diff{40};
     720                 :           1 :     const CAmount in_amt{3 * COIN};
     721                 :           1 :     const CAmount target{2 * COIN};
     722                 :           1 :     const CAmount excess{80};
     723                 :           1 :     const CAmount exact_target{in_amt - fee * 2}; // Maximum spendable amount after fees: no change, no excess
     724                 :             : 
     725                 :             :     // In the following, we test that the waste is calculated correctly in various scenarios.
     726                 :             :     // Usually, RecalculateWaste would compute change_fee and change_cost on basis of the
     727                 :             :     // change output type, current feerate, and discard_feerate, but we use fixed values
     728                 :             :     // across this test to make the test easier to understand.
     729                 :           1 :     {
     730                 :             :         // Waste with change is the change cost and difference between fee and long term fee
     731         [ +  - ]:           1 :         SelectionResult selection1{target, SelectionAlgorithm::MANUAL};
     732         [ +  - ]:           1 :         add_coin(1 * COIN, 1, selection1, /*fee=*/fee, /*long_term_fee=*/fee - fee_diff);
     733         [ +  - ]:           1 :         add_coin(2 * COIN, 2, selection1, fee, fee - fee_diff);
     734         [ +  - ]:           1 :         selection1.RecalculateWaste(min_viable_change, change_cost, change_fee);
     735   [ +  -  +  -  :           1 :         BOOST_CHECK_EQUAL(fee_diff * 2 + change_cost, selection1.GetWaste());
                   +  - ]
     736                 :             : 
     737                 :             :         // Waste will be greater when fee is greater, but long term fee is the same
     738         [ +  - ]:           1 :         SelectionResult selection2{target, SelectionAlgorithm::MANUAL};
     739         [ +  - ]:           1 :         add_coin(1 * COIN, 1, selection2, fee * 2, fee - fee_diff);
     740         [ +  - ]:           1 :         add_coin(2 * COIN, 2, selection2, fee * 2, fee - fee_diff);
     741         [ +  - ]:           1 :         selection2.RecalculateWaste(min_viable_change, change_cost, change_fee);
     742   [ +  -  +  -  :           1 :         BOOST_CHECK_GT(selection2.GetWaste(), selection1.GetWaste());
             +  -  +  - ]
     743                 :             : 
     744                 :             :         // Waste with change is the change cost and difference between fee and long term fee
     745                 :             :         // With long term fee greater than fee, waste should be less than when long term fee is less than fee
     746         [ +  - ]:           1 :         SelectionResult selection3{target, SelectionAlgorithm::MANUAL};
     747         [ +  - ]:           1 :         add_coin(1 * COIN, 1, selection3, fee, fee + fee_diff);
     748         [ +  - ]:           1 :         add_coin(2 * COIN, 2, selection3, fee, fee + fee_diff);
     749         [ +  - ]:           1 :         selection3.RecalculateWaste(min_viable_change, change_cost, change_fee);
     750   [ +  -  +  -  :           1 :         BOOST_CHECK_EQUAL(fee_diff * -2 + change_cost, selection3.GetWaste());
                   +  - ]
     751   [ +  -  +  -  :           1 :         BOOST_CHECK_LT(selection3.GetWaste(), selection1.GetWaste());
             +  -  +  - ]
     752                 :           1 :     }
     753                 :             : 
     754                 :           1 :     {
     755                 :             :         // Waste without change is the excess and difference between fee and long term fee
     756         [ +  - ]:           1 :         SelectionResult selection_nochange1{exact_target - excess, SelectionAlgorithm::MANUAL};
     757         [ +  - ]:           1 :         add_coin(1 * COIN, 1, selection_nochange1, fee, fee - fee_diff);
     758         [ +  - ]:           1 :         add_coin(2 * COIN, 2, selection_nochange1, fee, fee - fee_diff);
     759         [ +  - ]:           1 :         selection_nochange1.RecalculateWaste(min_viable_change, change_cost, change_fee);
     760   [ +  -  +  -  :           1 :         BOOST_CHECK_EQUAL(fee_diff * 2 + excess, selection_nochange1.GetWaste());
                   +  - ]
     761                 :             : 
     762                 :             :         // Waste without change is the excess and difference between fee and long term fee
     763                 :             :         // With long term fee greater than fee, waste should be less than when long term fee is less than fee
     764         [ +  - ]:           1 :         SelectionResult selection_nochange2{exact_target - excess, SelectionAlgorithm::MANUAL};
     765         [ +  - ]:           1 :         add_coin(1 * COIN, 1, selection_nochange2, fee, fee + fee_diff);
     766         [ +  - ]:           1 :         add_coin(2 * COIN, 2, selection_nochange2, fee, fee + fee_diff);
     767         [ +  - ]:           1 :         selection_nochange2.RecalculateWaste(min_viable_change, change_cost, change_fee);
     768   [ +  -  +  -  :           1 :         BOOST_CHECK_EQUAL(fee_diff * -2 + excess, selection_nochange2.GetWaste());
                   +  - ]
     769   [ +  -  +  -  :           1 :         BOOST_CHECK_LT(selection_nochange2.GetWaste(), selection_nochange1.GetWaste());
             +  -  +  - ]
     770                 :           1 :     }
     771                 :             : 
     772                 :           1 :     {
     773                 :             :         // Waste with change and fee == long term fee is just cost of change
     774         [ +  - ]:           1 :         SelectionResult selection{target, SelectionAlgorithm::MANUAL};
     775         [ +  - ]:           1 :         add_coin(1 * COIN, 1, selection, fee, fee);
     776         [ +  - ]:           1 :         add_coin(2 * COIN, 2, selection, fee, fee);
     777         [ +  - ]:           1 :         selection.RecalculateWaste(min_viable_change, change_cost, change_fee);
     778   [ +  -  +  -  :           1 :         BOOST_CHECK_EQUAL(change_cost, selection.GetWaste());
                   +  - ]
     779                 :           0 :     }
     780                 :             : 
     781                 :           1 :     {
     782                 :             :         // Waste without change and fee == long term fee is just the excess
     783         [ +  - ]:           1 :         SelectionResult selection{exact_target - excess, SelectionAlgorithm::MANUAL};
     784         [ +  - ]:           1 :         add_coin(1 * COIN, 1, selection, fee, fee);
     785         [ +  - ]:           1 :         add_coin(2 * COIN, 2, selection, fee, fee);
     786         [ +  - ]:           1 :         selection.RecalculateWaste(min_viable_change, change_cost, change_fee);
     787   [ +  -  +  -  :           1 :         BOOST_CHECK_EQUAL(excess, selection.GetWaste());
                   +  - ]
     788                 :           0 :     }
     789                 :             : 
     790                 :           1 :     {
     791                 :             :         // Waste is 0 when fee == long_term_fee, no change, and no excess
     792         [ +  - ]:           1 :         SelectionResult selection{exact_target, SelectionAlgorithm::MANUAL};
     793         [ +  - ]:           1 :         add_coin(1 * COIN, 1, selection, fee, fee);
     794         [ +  - ]:           1 :         add_coin(2 * COIN, 2, selection, fee, fee);
     795         [ +  - ]:           1 :         selection.RecalculateWaste(min_viable_change, change_cost , change_fee);
     796   [ +  -  +  -  :           1 :         BOOST_CHECK_EQUAL(0, selection.GetWaste());
                   +  - ]
     797                 :           0 :     }
     798                 :             : 
     799                 :           1 :     {
     800                 :             :         // Waste is 0 when (fee - long_term_fee) == (-cost_of_change), and no excess
     801         [ +  - ]:           1 :         SelectionResult selection{target, SelectionAlgorithm::MANUAL};
     802         [ +  - ]:           1 :         add_coin(1 * COIN, 1, selection, fee, fee + fee_diff);
     803         [ +  - ]:           1 :         add_coin(2 * COIN, 2, selection, fee, fee + fee_diff);
     804         [ +  - ]:           1 :         selection.RecalculateWaste(min_viable_change, /*change_cost=*/fee_diff * 2, change_fee);
     805   [ +  -  +  -  :           1 :         BOOST_CHECK_EQUAL(0, selection.GetWaste());
                   +  - ]
     806                 :           0 :     }
     807                 :             : 
     808                 :           1 :     {
     809                 :             :         // Waste is 0 when (fee - long_term_fee) == (-excess), no change cost
     810                 :           1 :         const CAmount new_target{exact_target - /*excess=*/fee_diff * 2};
     811         [ +  - ]:           1 :         SelectionResult selection{new_target, SelectionAlgorithm::MANUAL};
     812         [ +  - ]:           1 :         add_coin(1 * COIN, 1, selection, fee, fee + fee_diff);
     813         [ +  - ]:           1 :         add_coin(2 * COIN, 2, selection, fee, fee + fee_diff);
     814         [ +  - ]:           1 :         selection.RecalculateWaste(min_viable_change, change_cost, change_fee);
     815   [ +  -  +  -  :           1 :         BOOST_CHECK_EQUAL(0, selection.GetWaste());
                   +  - ]
     816                 :           0 :     }
     817                 :             : 
     818                 :           1 :     {
     819                 :             :         // Negative waste when the long term fee is greater than the current fee and the selected value == target
     820         [ +  - ]:           1 :         SelectionResult selection{exact_target, SelectionAlgorithm::MANUAL};
     821                 :           1 :         const CAmount target_waste1{-2 * fee_diff}; // = (2 * fee) - (2 * (fee + fee_diff))
     822         [ +  - ]:           1 :         add_coin(1 * COIN, 1, selection, fee, fee + fee_diff);
     823         [ +  - ]:           1 :         add_coin(2 * COIN, 2, selection, fee, fee + fee_diff);
     824         [ +  - ]:           1 :         selection.RecalculateWaste(min_viable_change, change_cost, change_fee);
     825   [ +  -  +  -  :           1 :         BOOST_CHECK_EQUAL(target_waste1, selection.GetWaste());
                   +  - ]
     826                 :           0 :     }
     827                 :             : 
     828                 :           1 :     {
     829                 :             :         // Negative waste when the long term fee is greater than the current fee and change_cost < - (inputs * (fee - long_term_fee))
     830         [ +  - ]:           1 :         SelectionResult selection{target, SelectionAlgorithm::MANUAL};
     831                 :           1 :         const CAmount large_fee_diff{90};
     832                 :           1 :         const CAmount target_waste2{-2 * large_fee_diff + change_cost};
     833                 :             :         // = (2 * fee) - (2 * (fee + large_fee_diff)) + change_cost
     834                 :             :         // = (2 * 100) - (2 * (100 + 90)) + 125
     835                 :             :         // = 200 - 380 + 125 = -55
     836                 :           1 :         assert(target_waste2 == -55);
     837         [ +  - ]:           1 :         add_coin(1 * COIN, 1, selection, fee, fee + large_fee_diff);
     838         [ +  - ]:           1 :         add_coin(2 * COIN, 2, selection, fee, fee + large_fee_diff);
     839         [ +  - ]:           1 :         selection.RecalculateWaste(min_viable_change, change_cost, change_fee);
     840   [ +  -  +  -  :           1 :         BOOST_CHECK_EQUAL(target_waste2, selection.GetWaste());
                   +  - ]
     841                 :           1 :     }
     842                 :           1 : }
     843                 :             : 
     844                 :             : 
     845   [ +  -  +  -  :           7 : BOOST_AUTO_TEST_CASE(bump_fee_test)
          +  -  +  -  -  
          +  +  -  +  -  
          +  -  +  -  +  
          -  +  -  -  +  
          +  -  +  -  +  
          -  +  -  +  -  
          +  -  -  +  +  
          -  +  -  +  -  
          +  -  +  -  +  
          -  +  -  -  +  
          +  -  +  -  +  
          -  +  -  +  -  
          +  -  -  +  +  
                      - ]
     846                 :             : {
     847                 :           1 :     const CAmount fee{100};
     848                 :           1 :     const CAmount min_viable_change{200};
     849                 :           1 :     const CAmount change_cost{125};
     850                 :           1 :     const CAmount change_fee{35};
     851                 :           1 :     const CAmount fee_diff{40};
     852                 :           1 :     const CAmount target{2 * COIN};
     853                 :             : 
     854                 :           1 :     {
     855         [ +  - ]:           1 :         SelectionResult selection{target, SelectionAlgorithm::MANUAL};
     856         [ +  - ]:           1 :         add_coin(1 * COIN, 1, selection, /*fee=*/fee, /*long_term_fee=*/fee + fee_diff);
     857         [ +  - ]:           1 :         add_coin(2 * COIN, 2, selection, fee, fee + fee_diff);
     858         [ +  - ]:           1 :         const std::vector<std::shared_ptr<COutput>> inputs = selection.GetShuffledInputVector();
     859                 :             : 
     860   [ -  +  +  + ]:           3 :         for (size_t i = 0; i < inputs.size(); ++i) {
     861                 :           2 :             inputs[i]->ApplyBumpFee(20*(i+1));
     862                 :             :         }
     863                 :             : 
     864         [ +  - ]:           1 :         selection.RecalculateWaste(min_viable_change, change_cost, change_fee);
     865                 :           1 :         CAmount expected_waste = fee_diff * -2 + change_cost + /*bump_fees=*/60;
     866   [ +  -  +  -  :           1 :         BOOST_CHECK_EQUAL(expected_waste, selection.GetWaste());
                   +  - ]
     867                 :             : 
     868         [ +  - ]:           1 :         selection.SetBumpFeeDiscount(30);
     869         [ +  - ]:           1 :         selection.RecalculateWaste(min_viable_change, change_cost, change_fee);
     870                 :           1 :         expected_waste = fee_diff * -2 + change_cost + /*bump_fees=*/60 - /*group_discount=*/30;
     871   [ +  -  +  -  :           1 :         BOOST_CHECK_EQUAL(expected_waste, selection.GetWaste());
                   +  - ]
     872                 :           1 :     }
     873                 :             : 
     874                 :           1 :     {
     875                 :             :         // Test with changeless transaction
     876                 :             :         //
     877                 :             :         // Bump fees and excess both contribute fully to the waste score,
     878                 :             :         // therefore, a bump fee group discount will not change the waste
     879                 :             :         // score as long as we do not create change in both instances.
     880                 :           1 :         CAmount changeless_target = 3 * COIN - 2 * fee - 100;
     881         [ +  - ]:           1 :         SelectionResult selection{changeless_target, SelectionAlgorithm::MANUAL};
     882         [ +  - ]:           1 :         add_coin(1 * COIN, 1, selection, /*fee=*/fee, /*long_term_fee=*/fee + fee_diff);
     883         [ +  - ]:           1 :         add_coin(2 * COIN, 2, selection, fee, fee + fee_diff);
     884         [ +  - ]:           1 :         const std::vector<std::shared_ptr<COutput>> inputs = selection.GetShuffledInputVector();
     885                 :             : 
     886   [ -  +  +  + ]:           3 :         for (size_t i = 0; i < inputs.size(); ++i) {
     887                 :           2 :             inputs[i]->ApplyBumpFee(20*(i+1));
     888                 :             :         }
     889                 :             : 
     890         [ +  - ]:           1 :         selection.RecalculateWaste(min_viable_change, change_cost, change_fee);
     891                 :           1 :         CAmount expected_waste = fee_diff * -2 + /*bump_fees=*/60 + /*excess = 100 - bump_fees*/40;
     892   [ +  -  +  -  :           1 :         BOOST_CHECK_EQUAL(expected_waste, selection.GetWaste());
                   +  - ]
     893                 :             : 
     894         [ +  - ]:           1 :         selection.SetBumpFeeDiscount(30);
     895         [ +  - ]:           1 :         selection.RecalculateWaste(min_viable_change, change_cost, change_fee);
     896                 :           1 :         expected_waste = fee_diff * -2 + /*bump_fees=*/60 - /*group_discount=*/30 + /*excess = 100 - bump_fees + group_discount*/70;
     897   [ +  -  +  -  :           1 :         BOOST_CHECK_EQUAL(expected_waste, selection.GetWaste());
                   +  - ]
     898                 :           1 :     }
     899                 :           1 : }
     900                 :             : 
     901   [ +  -  +  -  :           7 : BOOST_AUTO_TEST_CASE(effective_value_test)
          +  -  +  -  -  
          +  +  -  +  -  
          +  -  +  -  +  
          -  +  -  -  +  
          +  -  +  -  +  
          -  +  -  +  -  
          +  -  -  +  +  
          -  +  -  +  -  
          +  -  +  -  +  
          -  +  -  -  +  
          +  -  +  -  +  
          -  +  -  +  -  
          +  -  -  +  +  
                      - ]
     902                 :             : {
     903                 :           1 :     const int input_bytes = 148;
     904                 :           1 :     const CFeeRate feerate(1000);
     905                 :           1 :     const CAmount nValue = 10000;
     906                 :           1 :     const int nInput = 0;
     907                 :             : 
     908                 :           1 :     CMutableTransaction tx;
     909         [ +  - ]:           1 :     tx.vout.resize(1);
     910         [ +  - ]:           1 :     tx.vout[nInput].nValue = nValue;
     911                 :             : 
     912                 :             :     // standard case, pass feerate in constructor
     913   [ +  -  +  -  :           1 :     COutput output1(COutPoint(tx.GetHash(), nInput), tx.vout.at(nInput), /*depth=*/1, input_bytes, /*solvable=*/true, /*safe=*/true, /*time=*/0, /*from_me=*/false, feerate);
                   +  - ]
     914                 :           1 :     const CAmount expected_ev1 = 9852; // 10000 - 148
     915   [ +  -  +  - ]:           1 :     BOOST_CHECK_EQUAL(output1.GetEffectiveValue(), expected_ev1);
     916                 :             : 
     917                 :             :     // input bytes unknown (input_bytes = -1), pass feerate in constructor
     918   [ +  -  +  -  :           1 :     COutput output2(COutPoint(tx.GetHash(), nInput), tx.vout.at(nInput), /*depth=*/1, /*input_bytes=*/-1, /*solvable=*/true, /*safe=*/true, /*time=*/0, /*from_me=*/ false, feerate);
                   +  - ]
     919   [ +  -  +  - ]:           1 :     BOOST_CHECK_EQUAL(output2.GetEffectiveValue(), nValue); // The effective value should be equal to the absolute value if input_bytes is -1
     920                 :             : 
     921                 :             :     // negative effective value, pass feerate in constructor
     922   [ +  -  +  -  :           1 :     COutput output3(COutPoint(tx.GetHash(), nInput), tx.vout.at(nInput), /*depth=*/1, input_bytes, /*solvable=*/true, /*safe=*/true, /*time=*/0, /*from_me=*/false, CFeeRate(100000));
                   +  - ]
     923                 :           1 :     const CAmount expected_ev3 = -4800; // 10000 - 14800
     924   [ +  -  +  - ]:           1 :     BOOST_CHECK_EQUAL(output3.GetEffectiveValue(), expected_ev3);
     925                 :             : 
     926                 :             :     // standard case, pass fees in constructor
     927                 :           1 :     const CAmount fees = 148;
     928   [ +  -  +  -  :           1 :     COutput output4(COutPoint(tx.GetHash(), nInput), tx.vout.at(nInput), /*depth=*/1, input_bytes, /*solvable=*/true, /*safe=*/true, /*time=*/0, /*from_me=*/false, fees);
                   +  - ]
     929   [ +  -  +  - ]:           1 :     BOOST_CHECK_EQUAL(output4.GetEffectiveValue(), expected_ev1);
     930                 :             : 
     931                 :             :     // input bytes unknown (input_bytes = -1), pass fees in constructor
     932   [ +  -  +  -  :           1 :     COutput output5(COutPoint(tx.GetHash(), nInput), tx.vout.at(nInput), /*depth=*/1, /*input_bytes=*/-1, /*solvable=*/true, /*safe=*/true, /*time=*/0, /*from_me=*/false, /*fees=*/0);
                   +  - ]
     933   [ +  -  +  - ]:           1 :     BOOST_CHECK_EQUAL(output5.GetEffectiveValue(), nValue); // The effective value should be equal to the absolute value if input_bytes is -1
     934                 :           2 : }
     935                 :             : 
     936                 :           7 : static util::Result<SelectionResult> CoinGrinder(const CAmount& target,
     937                 :             :                                                     const CoinSelectionParams& cs_params,
     938                 :             :                                                     const node::NodeContext& m_node,
     939                 :             :                                                     int max_selection_weight,
     940                 :             :                                                     std::function<CoinsResult(CWallet&)> coin_setup)
     941                 :             : {
     942         [ +  - ]:           7 :     std::unique_ptr<CWallet> wallet = NewWallet(m_node);
     943         [ +  - ]:           7 :     CoinEligibilityFilter filter(0, 0, 0); // accept all coins without ancestors
     944   [ +  -  +  -  :          14 :     Groups group = GroupOutputs(*wallet, coin_setup(*wallet), cs_params, {{filter}})[filter].all_groups;
          +  -  +  -  +  
                -  +  - ]
     945         [ +  - ]:           7 :     return CoinGrinder(group.positive_group, target, cs_params.m_min_change_target, max_selection_weight);
     946         [ +  - ]:          14 : }
     947                 :             : 
     948   [ +  -  +  -  :           7 : BOOST_AUTO_TEST_CASE(coin_grinder_tests)
          +  -  +  -  -  
          +  +  -  +  -  
          +  -  +  -  +  
          -  +  -  -  +  
          +  -  +  -  +  
          -  +  -  +  -  
          +  -  -  +  +  
          -  +  -  +  -  
          +  -  +  -  +  
          -  +  -  -  +  
          +  -  +  -  +  
          -  +  -  +  -  
          +  -  -  +  +  
                      - ]
     949                 :             : {
     950                 :             :     // Test Coin Grinder:
     951                 :             :     // 1) Insufficient funds, select all provided coins and fail.
     952                 :             :     // 2) Exceeded max weight, coin selection always surpasses the max allowed weight.
     953                 :             :     // 3) Select coins without surpassing the max weight (some coins surpasses the max allowed weight, some others not)
     954                 :             :     // 4) Test that two less valuable UTXOs with a combined lower weight are preferred over a more valuable heavier UTXO
     955                 :             :     // 5) Test finding a solution in a UTXO pool with mixed weights
     956                 :             :     // 6) Test that the lightest solution among many clones is found
     957                 :             :     // 7) Test that lots of tiny UTXOs can be skipped if they are too heavy while there are enough funds in lookahead
     958                 :             : 
     959                 :           1 :     FastRandomContext rand;
     960         [ +  - ]:           1 :     CoinSelectionParams dummy_params{ // Only used to provide the 'avoid_partial' flag.
     961                 :             :             rand,
     962                 :             :             /*change_output_size=*/34,
     963                 :             :             /*change_spend_size=*/68,
     964                 :             :             /*min_change_target=*/CENT,
     965                 :           1 :             /*effective_feerate=*/CFeeRate(5000),
     966                 :           1 :             /*long_term_feerate=*/CFeeRate(2000),
     967                 :           1 :             /*discard_feerate=*/CFeeRate(1000),
     968                 :             :             /*tx_noinputs_size=*/10 + 34, // static header size + output size
     969                 :             :             /*avoid_partial=*/false,
     970         [ +  - ]:           1 :     };
     971                 :             : 
     972                 :           1 :     {
     973                 :             :         // #########################################################
     974                 :             :         // 1) Insufficient funds, select all provided coins and fail
     975                 :             :         // #########################################################
     976                 :           1 :         CAmount target = 49.5L * COIN;
     977                 :           1 :         int max_selection_weight = 10'000; // high enough to not fail for this reason.
     978         [ +  - ]:           2 :         const auto& res = CoinGrinder(target, dummy_params, m_node, max_selection_weight, [&](CWallet& wallet) {
     979                 :           1 :             CoinsResult available_coins;
     980         [ +  + ]:          11 :             for (int j = 0; j < 10; ++j) {
     981         [ +  - ]:          10 :                 add_coin(available_coins, wallet, CAmount(1 * COIN));
     982         [ +  - ]:          10 :                 add_coin(available_coins, wallet, CAmount(2 * COIN));
     983                 :             :             }
     984                 :           1 :             return available_coins;
     985         [ +  - ]:           1 :         });
     986   [ +  -  +  -  :           2 :         BOOST_CHECK(!res);
                   +  - ]
     987   [ +  -  +  -  :           3 :         BOOST_CHECK(util::ErrorString(res).empty()); // empty means "insufficient funds"
                   +  - ]
     988                 :           0 :     }
     989                 :             : 
     990                 :           1 :     {
     991                 :             :         // ###########################
     992                 :             :         // 2) Test max weight exceeded
     993                 :             :         // ###########################
     994                 :           1 :         CAmount target = 29.5L * COIN;
     995                 :           1 :         int max_selection_weight = 3000;
     996         [ +  - ]:           2 :         const auto& res = CoinGrinder(target, dummy_params, m_node, max_selection_weight, [&](CWallet& wallet) {
     997                 :           1 :             CoinsResult available_coins;
     998         [ +  + ]:          11 :             for (int j = 0; j < 10; ++j) {
     999         [ +  - ]:          10 :                 add_coin(available_coins, wallet, CAmount(1 * COIN), CFeeRate(5000), 144, false, 0, true);
    1000         [ +  - ]:          10 :                 add_coin(available_coins, wallet, CAmount(2 * COIN), CFeeRate(5000), 144, false, 0, true);
    1001                 :             :             }
    1002                 :           1 :             return available_coins;
    1003         [ +  - ]:           1 :         });
    1004   [ +  -  +  -  :           2 :         BOOST_CHECK(!res);
                   +  - ]
    1005   [ +  -  +  -  :           3 :         BOOST_CHECK(util::ErrorString(res).original.find("The inputs size exceeds the maximum weight") != std::string::npos);
                   +  - ]
    1006                 :           0 :     }
    1007                 :             : 
    1008                 :           1 :     {
    1009                 :             :         // ###############################################################################################################
    1010                 :             :         // 3) Test that the lowest-weight solution is found when some combinations would exceed the allowed weight
    1011                 :             :         // ################################################################################################################
    1012                 :           1 :         CAmount target = 25.33L * COIN;
    1013                 :           1 :         int max_selection_weight = 10'000; // WU
    1014         [ +  - ]:           2 :         const auto& res = CoinGrinder(target, dummy_params, m_node, max_selection_weight, [&](CWallet& wallet) {
    1015                 :           1 :             CoinsResult available_coins;
    1016         [ +  + ]:          61 :             for (int j = 0; j < 60; ++j) { // 60 UTXO --> 19,8 BTC total --> 60 × 272 WU = 16320 WU
    1017         [ +  - ]:          60 :                 add_coin(available_coins, wallet, CAmount(0.33 * COIN), CFeeRate(5000), 144, false, 0, true);
    1018                 :             :             }
    1019         [ +  + ]:          11 :             for (int i = 0; i < 10; i++) { // 10 UTXO --> 20 BTC total --> 10 × 272 WU = 2720 WU
    1020         [ +  - ]:          10 :                 add_coin(available_coins, wallet, CAmount(2 * COIN), CFeeRate(5000), 144, false, 0, true);
    1021                 :             :             }
    1022                 :           1 :             return available_coins;
    1023         [ +  - ]:           1 :         });
    1024                 :           1 :         SelectionResult expected_result(CAmount(0), SelectionAlgorithm::CG);
    1025         [ +  + ]:          11 :         for (int i = 0; i < 10; ++i) {
    1026         [ +  - ]:          10 :             add_coin(2 * COIN, i, expected_result);
    1027                 :             :         }
    1028         [ +  + ]:          18 :         for (int j = 0; j < 17; ++j) {
    1029         [ +  - ]:          17 :             add_coin(0.33 * COIN, j + 10, expected_result);
    1030                 :             :         }
    1031   [ +  -  +  -  :           2 :         BOOST_CHECK(EquivalentResult(expected_result, *res));
             +  -  +  - ]
    1032                 :             :         // Demonstrate how following improvements reduce iteration count and catch any regressions in the future.
    1033                 :           1 :         size_t expected_attempts = 37;
    1034   [ +  -  +  -  :           2 :         BOOST_CHECK_MESSAGE(res->GetSelectionsEvaluated() == expected_attempts, strprintf("Expected %i attempts, but got %i", expected_attempts, res->GetSelectionsEvaluated()));
          +  -  +  -  +  
                      - ]
    1035                 :           1 :     }
    1036                 :             : 
    1037                 :           1 :     {
    1038                 :             :         // #################################################################################################################
    1039                 :             :         // 4) Test that two less valuable UTXOs with a combined lower weight are preferred over a more valuable heavier UTXO
    1040                 :             :         // #################################################################################################################
    1041                 :           1 :         CAmount target =  1.9L * COIN;
    1042                 :           1 :         int max_selection_weight = 400'000; // WU
    1043         [ +  - ]:           2 :         const auto& res = CoinGrinder(target, dummy_params, m_node, max_selection_weight, [&](CWallet& wallet) {
    1044         [ +  - ]:           1 :             CoinsResult available_coins;
    1045         [ +  - ]:           1 :             add_coin(available_coins, wallet, CAmount(2 * COIN), CFeeRate(5000), 144, false, 0, true, 148);
    1046         [ +  - ]:           1 :             add_coin(available_coins, wallet, CAmount(1 * COIN), CFeeRate(5000), 144, false, 0, true, 68);
    1047         [ +  - ]:           1 :             add_coin(available_coins, wallet, CAmount(1 * COIN), CFeeRate(5000), 144, false, 0, true, 68);
    1048                 :           1 :             return available_coins;
    1049         [ +  - ]:           1 :         });
    1050         [ +  - ]:           1 :         SelectionResult expected_result(CAmount(0), SelectionAlgorithm::CG);
    1051         [ +  - ]:           1 :         add_coin(1 * COIN, 1, expected_result);
    1052         [ +  - ]:           1 :         add_coin(1 * COIN, 2, expected_result);
    1053   [ +  -  +  -  :           2 :         BOOST_CHECK(EquivalentResult(expected_result, *res));
             +  -  +  - ]
    1054                 :             :         // Demonstrate how following improvements reduce iteration count and catch any regressions in the future.
    1055                 :           1 :         size_t expected_attempts = 3;
    1056   [ +  -  +  -  :           2 :         BOOST_CHECK_MESSAGE(res->GetSelectionsEvaluated() == expected_attempts, strprintf("Expected %i attempts, but got %i", expected_attempts, res->GetSelectionsEvaluated()));
          +  -  +  -  +  
                      - ]
    1057                 :           1 :     }
    1058                 :             : 
    1059                 :           1 :     {
    1060                 :             :         // ###############################################################################################################
    1061                 :             :         // 5) Test finding a solution in a UTXO pool with mixed weights
    1062                 :             :         // ################################################################################################################
    1063                 :           1 :         CAmount target = 30L * COIN;
    1064                 :           1 :         int max_selection_weight = 400'000; // WU
    1065         [ +  - ]:           2 :         const auto& res = CoinGrinder(target, dummy_params, m_node, max_selection_weight, [&](CWallet& wallet) {
    1066                 :           1 :             CoinsResult available_coins;
    1067         [ +  + ]:           6 :             for (int j = 0; j < 5; ++j) {
    1068                 :             :                 // Add heavy coins {3, 6, 9, 12, 15}
    1069         [ +  - ]:           5 :                 add_coin(available_coins, wallet, CAmount((3 + 3 * j) * COIN), CFeeRate(5000), 144, false, 0, true, 350);
    1070                 :             :                 // Add medium coins {2, 5, 8, 11, 14}
    1071         [ +  - ]:           5 :                 add_coin(available_coins, wallet, CAmount((2 + 3 * j) * COIN), CFeeRate(5000), 144, false, 0, true, 250);
    1072                 :             :                 // Add light coins {1, 4, 7, 10, 13}
    1073         [ +  - ]:           5 :                 add_coin(available_coins, wallet, CAmount((1 + 3 * j) * COIN), CFeeRate(5000), 144, false, 0, true, 150);
    1074                 :             :             }
    1075                 :           1 :             return available_coins;
    1076         [ +  - ]:           1 :         });
    1077   [ +  -  +  -  :           2 :         BOOST_CHECK(res);
                   +  - ]
    1078         [ +  - ]:           1 :         SelectionResult expected_result(CAmount(0), SelectionAlgorithm::CG);
    1079         [ +  - ]:           1 :         add_coin(14 * COIN, 1, expected_result);
    1080         [ +  - ]:           1 :         add_coin(13 * COIN, 2, expected_result);
    1081         [ +  - ]:           1 :         add_coin(4 * COIN, 3, expected_result);
    1082   [ +  -  +  -  :           2 :         BOOST_CHECK(EquivalentResult(expected_result, *res));
             +  -  +  - ]
    1083                 :             :         // Demonstrate how following improvements reduce iteration count and catch any regressions in the future.
    1084                 :           1 :         size_t expected_attempts = 92;
    1085   [ +  -  +  -  :           2 :         BOOST_CHECK_MESSAGE(res->GetSelectionsEvaluated() == expected_attempts, strprintf("Expected %i attempts, but got %i", expected_attempts, res->GetSelectionsEvaluated()));
          +  -  +  -  +  
                      - ]
    1086                 :           1 :     }
    1087                 :             : 
    1088                 :           1 :     {
    1089                 :             :         // #################################################################################################################
    1090                 :             :         // 6) Test that the lightest solution among many clones is found
    1091                 :             :         // #################################################################################################################
    1092                 :           1 :         CAmount target =  9.9L * COIN;
    1093                 :           1 :         int max_selection_weight = 400'000; // WU
    1094         [ +  - ]:           2 :         const auto& res = CoinGrinder(target, dummy_params, m_node, max_selection_weight, [&](CWallet& wallet) {
    1095         [ +  - ]:           1 :             CoinsResult available_coins;
    1096                 :             :             // Expected Result: 4 + 3 + 2 + 1 = 10 BTC at 400 vB
    1097         [ +  - ]:           1 :             add_coin(available_coins, wallet, CAmount(4 * COIN), CFeeRate(5000), 144, false, 0, true, 100);
    1098         [ +  - ]:           1 :             add_coin(available_coins, wallet, CAmount(3 * COIN), CFeeRate(5000), 144, false, 0, true, 100);
    1099         [ +  - ]:           1 :             add_coin(available_coins, wallet, CAmount(2 * COIN), CFeeRate(5000), 144, false, 0, true, 100);
    1100         [ +  - ]:           1 :             add_coin(available_coins, wallet, CAmount(1 * COIN), CFeeRate(5000), 144, false, 0, true, 100);
    1101                 :             :             // Distracting clones:
    1102         [ +  + ]:         101 :             for (int j = 0; j < 100; ++j) {
    1103         [ +  - ]:         100 :                 add_coin(available_coins, wallet, CAmount(8 * COIN), CFeeRate(5000), 144, false, 0, true, 1000);
    1104                 :             :             }
    1105         [ +  + ]:         101 :             for (int j = 0; j < 100; ++j) {
    1106         [ +  - ]:         100 :                 add_coin(available_coins, wallet, CAmount(7 * COIN), CFeeRate(5000), 144, false, 0, true, 800);
    1107                 :             :             }
    1108         [ +  + ]:         101 :             for (int j = 0; j < 100; ++j) {
    1109         [ +  - ]:         100 :                 add_coin(available_coins, wallet, CAmount(6 * COIN), CFeeRate(5000), 144, false, 0, true, 600);
    1110                 :             :             }
    1111         [ +  + ]:         101 :             for (int j = 0; j < 100; ++j) {
    1112         [ +  - ]:         100 :                 add_coin(available_coins, wallet, CAmount(5 * COIN), CFeeRate(5000), 144, false, 0, true, 400);
    1113                 :             :             }
    1114                 :           1 :             return available_coins;
    1115         [ +  - ]:           1 :         });
    1116         [ +  - ]:           1 :         SelectionResult expected_result(CAmount(0), SelectionAlgorithm::CG);
    1117         [ +  - ]:           1 :         add_coin(4 * COIN, 0, expected_result);
    1118         [ +  - ]:           1 :         add_coin(3 * COIN, 0, expected_result);
    1119         [ +  - ]:           1 :         add_coin(2 * COIN, 0, expected_result);
    1120         [ +  - ]:           1 :         add_coin(1 * COIN, 0, expected_result);
    1121   [ +  -  +  -  :           2 :         BOOST_CHECK(EquivalentResult(expected_result, *res));
             +  -  +  - ]
    1122                 :             :         // Demonstrate how following improvements reduce iteration count and catch any regressions in the future.
    1123                 :           1 :         size_t expected_attempts = 38;
    1124   [ +  -  +  -  :           2 :         BOOST_CHECK_MESSAGE(res->GetSelectionsEvaluated() == expected_attempts, strprintf("Expected %i attempts, but got %i", expected_attempts, res->GetSelectionsEvaluated()));
          +  -  +  -  +  
                      - ]
    1125                 :           1 :     }
    1126                 :             : 
    1127                 :           1 :     {
    1128                 :             :         // #################################################################################################################
    1129                 :             :         // 7) Test that lots of tiny UTXOs can be skipped if they are too heavy while there are enough funds in lookahead
    1130                 :             :         // #################################################################################################################
    1131                 :           1 :         CAmount target =  1.9L * COIN;
    1132                 :           1 :         int max_selection_weight = 40000; // WU
    1133         [ +  - ]:           2 :         const auto& res = CoinGrinder(target, dummy_params, m_node, max_selection_weight, [&](CWallet& wallet) {
    1134         [ +  - ]:           1 :             CoinsResult available_coins;
    1135         [ +  - ]:           1 :             add_coin(available_coins, wallet, CAmount(1.8 * COIN), CFeeRate(5000), 144, false, 0, true, 2500);
    1136         [ +  - ]:           1 :             add_coin(available_coins, wallet, CAmount(1 * COIN), CFeeRate(5000), 144, false, 0, true, 1000);
    1137         [ +  - ]:           1 :             add_coin(available_coins, wallet, CAmount(1 * COIN), CFeeRate(5000), 144, false, 0, true, 1000);
    1138         [ +  + ]:         101 :             for (int j = 0; j < 100; ++j) {
    1139                 :             :                 // make a 100 unique coins only differing by one sat
    1140         [ +  - ]:         100 :                 add_coin(available_coins, wallet, CAmount(0.01 * COIN + j), CFeeRate(5000), 144, false, 0, true, 110);
    1141                 :             :             }
    1142                 :           1 :             return available_coins;
    1143         [ +  - ]:           1 :         });
    1144         [ +  - ]:           1 :         SelectionResult expected_result(CAmount(0), SelectionAlgorithm::CG);
    1145         [ +  - ]:           1 :         add_coin(1 * COIN, 1, expected_result);
    1146         [ +  - ]:           1 :         add_coin(1 * COIN, 2, expected_result);
    1147   [ +  -  +  -  :           2 :         BOOST_CHECK(EquivalentResult(expected_result, *res));
             +  -  +  - ]
    1148                 :             :         // Demonstrate how following improvements reduce iteration count and catch any regressions in the future.
    1149                 :           1 :         size_t expected_attempts = 7;
    1150   [ +  -  +  -  :           2 :         BOOST_CHECK_MESSAGE(res->GetSelectionsEvaluated() == expected_attempts, strprintf("Expected %i attempts, but got %i", expected_attempts, res->GetSelectionsEvaluated()));
          +  -  +  -  +  
                      - ]
    1151                 :           1 :     }
    1152                 :           1 : }
    1153                 :             : 
    1154                 :           3 : static util::Result<SelectionResult> SelectCoinsSRD(const CAmount& target,
    1155                 :             :                                                     const CoinSelectionParams& cs_params,
    1156                 :             :                                                     const node::NodeContext& m_node,
    1157                 :             :                                                     int max_selection_weight,
    1158                 :             :                                                     std::function<CoinsResult(CWallet&)> coin_setup)
    1159                 :             : {
    1160         [ +  - ]:           3 :     std::unique_ptr<CWallet> wallet = NewWallet(m_node);
    1161         [ +  - ]:           3 :     CoinEligibilityFilter filter(0, 0, 0); // accept all coins without ancestors
    1162   [ +  -  +  -  :           6 :     Groups group = GroupOutputs(*wallet, coin_setup(*wallet), cs_params, {{filter}})[filter].all_groups;
          +  -  +  -  +  
                -  +  - ]
    1163         [ +  - ]:           3 :     return SelectCoinsSRD(group.positive_group, target, cs_params.m_change_fee, cs_params.rng_fast, max_selection_weight);
    1164         [ +  - ]:           6 : }
    1165                 :             : 
    1166   [ +  -  +  -  :           7 : BOOST_AUTO_TEST_CASE(srd_tests)
          +  -  +  -  -  
          +  +  -  +  -  
          +  -  +  -  +  
          -  +  -  -  +  
          +  -  +  -  +  
          -  +  -  +  -  
          +  -  -  +  +  
          -  +  -  +  -  
          +  -  +  -  +  
          -  +  -  -  +  
          +  -  +  -  +  
          -  +  -  +  -  
          +  -  -  +  +  
                      - ]
    1167                 :             : {
    1168                 :             :     // Test SRD:
    1169                 :             :     // 1) Insufficient funds, select all provided coins and fail.
    1170                 :             :     // 2) Exceeded max weight, coin selection always surpasses the max allowed weight.
    1171                 :             :     // 3) Select coins without surpassing the max weight (some coins surpasses the max allowed weight, some others not)
    1172                 :             : 
    1173                 :           1 :     FastRandomContext rand;
    1174         [ +  - ]:           1 :     CoinSelectionParams dummy_params{ // Only used to provide the 'avoid_partial' flag.
    1175                 :             :             rand,
    1176                 :             :             /*change_output_size=*/34,
    1177                 :             :             /*change_spend_size=*/68,
    1178                 :             :             /*min_change_target=*/CENT,
    1179                 :           1 :             /*effective_feerate=*/CFeeRate(0),
    1180                 :           1 :             /*long_term_feerate=*/CFeeRate(0),
    1181                 :           1 :             /*discard_feerate=*/CFeeRate(0),
    1182                 :             :             /*tx_noinputs_size=*/10 + 34, // static header size + output size
    1183                 :             :             /*avoid_partial=*/false,
    1184         [ +  - ]:           1 :     };
    1185                 :             : 
    1186                 :           1 :     {
    1187                 :             :         // #########################################################
    1188                 :             :         // 1) Insufficient funds, select all provided coins and fail
    1189                 :             :         // #########################################################
    1190                 :           1 :         CAmount target = 49.5L * COIN;
    1191                 :           1 :         int max_selection_weight = 10000; // high enough to not fail for this reason.
    1192         [ +  - ]:           2 :         const auto& res = SelectCoinsSRD(target, dummy_params, m_node, max_selection_weight, [&](CWallet& wallet) {
    1193                 :           1 :             CoinsResult available_coins;
    1194         [ +  + ]:          11 :             for (int j = 0; j < 10; ++j) {
    1195         [ +  - ]:          10 :                 add_coin(available_coins, wallet, CAmount(1 * COIN));
    1196         [ +  - ]:          10 :                 add_coin(available_coins, wallet, CAmount(2 * COIN));
    1197                 :             :             }
    1198                 :           1 :             return available_coins;
    1199         [ +  - ]:           1 :         });
    1200   [ +  -  +  -  :           2 :         BOOST_CHECK(!res);
                   +  - ]
    1201   [ +  -  +  -  :           3 :         BOOST_CHECK(util::ErrorString(res).empty()); // empty means "insufficient funds"
                   +  - ]
    1202                 :           0 :     }
    1203                 :             : 
    1204                 :           1 :     {
    1205                 :             :         // ###########################
    1206                 :             :         // 2) Test max weight exceeded
    1207                 :             :         // ###########################
    1208                 :           1 :         CAmount target = 49.5L * COIN;
    1209                 :           1 :         int max_selection_weight = 3000;
    1210         [ +  - ]:           2 :         const auto& res = SelectCoinsSRD(target, dummy_params, m_node, max_selection_weight, [&](CWallet& wallet) {
    1211                 :           1 :             CoinsResult available_coins;
    1212         [ +  + ]:          11 :             for (int j = 0; j < 10; ++j) {
    1213                 :             :                 /* 10 × 1 BTC + 10 × 2 BTC = 30 BTC. 20 × 272 WU = 5440 WU */
    1214         [ +  - ]:          10 :                 add_coin(available_coins, wallet, CAmount(1 * COIN), CFeeRate(0), 144, false, 0, true);
    1215         [ +  - ]:          10 :                 add_coin(available_coins, wallet, CAmount(2 * COIN), CFeeRate(0), 144, false, 0, true);
    1216                 :             :             }
    1217                 :           1 :             return available_coins;
    1218         [ +  - ]:           1 :         });
    1219   [ +  -  +  -  :           2 :         BOOST_CHECK(!res);
                   +  - ]
    1220   [ +  -  +  -  :           3 :         BOOST_CHECK(util::ErrorString(res).original.find("The inputs size exceeds the maximum weight") != std::string::npos);
                   +  - ]
    1221                 :           0 :     }
    1222                 :             : 
    1223                 :           1 :     {
    1224                 :             :         // ################################################################################################################
    1225                 :             :         // 3) Test that SRD result does not exceed the max weight
    1226                 :             :         // ################################################################################################################
    1227                 :           1 :         CAmount target = 25.33L * COIN;
    1228                 :           1 :         int max_selection_weight = 10000; // WU
    1229         [ +  - ]:           2 :         const auto& res = SelectCoinsSRD(target, dummy_params, m_node, max_selection_weight, [&](CWallet& wallet) {
    1230                 :           1 :             CoinsResult available_coins;
    1231         [ +  + ]:          61 :             for (int j = 0; j < 60; ++j) { // 60 UTXO --> 19,8 BTC total --> 60 × 272 WU = 16320 WU
    1232         [ +  - ]:          60 :                 add_coin(available_coins, wallet, CAmount(0.33 * COIN), CFeeRate(0), 144, false, 0, true);
    1233                 :             :             }
    1234         [ +  + ]:          11 :             for (int i = 0; i < 10; i++) { // 10 UTXO --> 20 BTC total --> 10 × 272 WU = 2720 WU
    1235         [ +  - ]:          10 :                 add_coin(available_coins, wallet, CAmount(2 * COIN), CFeeRate(0), 144, false, 0, true);
    1236                 :             :             }
    1237                 :           1 :             return available_coins;
    1238         [ +  - ]:           2 :         });
    1239   [ +  -  +  -  :           2 :         BOOST_CHECK(res);
                   +  - ]
    1240   [ +  -  +  - ]:           2 :         BOOST_CHECK(res->GetWeight() <= max_selection_weight);
    1241                 :             :     }
    1242                 :           1 : }
    1243                 :             : 
    1244                 :           3 : static util::Result<SelectionResult> select_coins(const CAmount& target, const CoinSelectionParams& cs_params, const CCoinControl& cc, std::function<CoinsResult(CWallet&)> coin_setup, const node::NodeContext& m_node)
    1245                 :             : {
    1246         [ +  - ]:           3 :     std::unique_ptr<CWallet> wallet = NewWallet(m_node);
    1247         [ +  - ]:           3 :     auto available_coins = coin_setup(*wallet);
    1248                 :             : 
    1249         [ +  - ]:           3 :     LOCK(wallet->cs_wallet);
    1250                 :           0 :     auto result = SelectCoins(*wallet, available_coins, /*pre_set_inputs=*/ {}, target, cc, cs_params);
    1251         [ +  + ]:           3 :     if (result) {
    1252   [ +  -  +  - ]:           2 :         const auto signedTxSize = 10 + 34 + 68 * result->GetInputSet().size(); // static header size + output size + inputs size (P2WPKH)
    1253   [ +  -  +  - ]:           2 :         BOOST_CHECK_LE(signedTxSize * WITNESS_SCALE_FACTOR, MAX_STANDARD_TX_WEIGHT);
    1254                 :             : 
    1255   [ +  -  +  -  :           2 :         BOOST_CHECK_GE(result->GetSelectedValue(), target);
                   +  - ]
    1256                 :             :     }
    1257         [ +  - ]:           3 :     return result;
    1258   [ +  -  +  - ]:           9 : }
    1259                 :             : 
    1260                 :           3 : static bool has_coin(const CoinSet& set, CAmount amount)
    1261                 :             : {
    1262         [ +  + ]:        1161 :     return std::any_of(set.begin(), set.end(), [&](const auto& coin) { return coin->GetEffectiveValue() == amount; });
    1263                 :             : }
    1264                 :             : 
    1265   [ +  -  +  -  :           7 : BOOST_AUTO_TEST_CASE(check_max_selection_weight)
          +  -  +  -  -  
          +  +  -  +  -  
          +  -  +  -  +  
          -  +  -  -  +  
          +  -  +  -  +  
          -  +  -  +  -  
          +  -  -  +  +  
          -  +  -  +  -  
          +  -  +  -  +  
          -  +  -  -  +  
          +  -  +  -  +  
          -  +  -  +  -  
          +  -  -  +  +  
                      - ]
    1266                 :             : {
    1267                 :           1 :     const CAmount target = 49.5L * COIN;
    1268                 :           1 :     CCoinControl cc;
    1269                 :             : 
    1270                 :           1 :     FastRandomContext rand;
    1271         [ +  - ]:           1 :     CoinSelectionParams cs_params{
    1272                 :             :         rand,
    1273                 :             :         /*change_output_size=*/34,
    1274                 :             :         /*change_spend_size=*/68,
    1275                 :             :         /*min_change_target=*/CENT,
    1276                 :           1 :         /*effective_feerate=*/CFeeRate(0),
    1277                 :           1 :         /*long_term_feerate=*/CFeeRate(0),
    1278                 :           1 :         /*discard_feerate=*/CFeeRate(0),
    1279                 :             :         /*tx_noinputs_size=*/10 + 34, // static header size + output size
    1280                 :             :         /*avoid_partial=*/false,
    1281         [ +  - ]:           1 :     };
    1282                 :             : 
    1283                 :           1 :     int max_weight = MAX_STANDARD_TX_WEIGHT - WITNESS_SCALE_FACTOR * (cs_params.tx_noinputs_size + cs_params.change_output_size);
    1284                 :           1 :     {
    1285                 :             :         // Scenario 1:
    1286                 :             :         // The actor starts with 1x 50.0 BTC and 1515x 0.033 BTC (~100.0 BTC total) unspent outputs
    1287                 :             :         // Then tries to spend 49.5 BTC
    1288                 :             :         // The 50.0 BTC output should be selected, because the transaction would otherwise be too large
    1289                 :             : 
    1290                 :             :         // Perform selection
    1291                 :             : 
    1292                 :           1 :         const auto result = select_coins(
    1293         [ +  - ]:           2 :             target, cs_params, cc, [&](CWallet& wallet) {
    1294                 :           1 :                 CoinsResult available_coins;
    1295         [ +  + ]:        1516 :                 for (int j = 0; j < 1515; ++j) {
    1296         [ +  - ]:        1515 :                     add_coin(available_coins, wallet, CAmount(0.033 * COIN), CFeeRate(0), 144, false, 0, true);
    1297                 :             :                 }
    1298                 :             : 
    1299         [ +  - ]:           1 :                 add_coin(available_coins, wallet, CAmount(50 * COIN), CFeeRate(0), 144, false, 0, true);
    1300                 :           1 :                 return available_coins;
    1301                 :           0 :             },
    1302         [ +  - ]:           1 :             m_node);
    1303                 :             : 
    1304   [ +  -  +  -  :           2 :         BOOST_CHECK(result);
                   +  - ]
    1305                 :             :         // Verify that the 50 BTC UTXO was selected, and result is below max_weight
    1306   [ +  -  +  -  :           2 :         BOOST_CHECK(has_coin(result->GetInputSet(), CAmount(50 * COIN)));
             +  -  +  - ]
    1307   [ +  -  +  - ]:           1 :         BOOST_CHECK_LE(result->GetWeight(), max_weight);
    1308                 :           0 :     }
    1309                 :             : 
    1310                 :           1 :     {
    1311                 :             :         // Scenario 2:
    1312                 :             : 
    1313                 :             :         // The actor starts with 400x 0.0625 BTC and 2000x 0.025 BTC (75.0 BTC total) unspent outputs
    1314                 :             :         // Then tries to spend 49.5 BTC
    1315                 :             :         // A combination of coins should be selected, such that the created transaction is not too large
    1316                 :             : 
    1317                 :             :         // Perform selection
    1318                 :           1 :         const auto result = select_coins(
    1319         [ +  - ]:           2 :             target, cs_params, cc, [&](CWallet& wallet) {
    1320                 :           1 :                 CoinsResult available_coins;
    1321         [ +  + ]:         401 :                 for (int j = 0; j < 400; ++j) {
    1322         [ +  - ]:         400 :                     add_coin(available_coins, wallet, CAmount(0.0625 * COIN), CFeeRate(0), 144, false, 0, true);
    1323                 :             :                 }
    1324         [ +  + ]:        2001 :                 for (int j = 0; j < 2000; ++j) {
    1325         [ +  - ]:        2000 :                     add_coin(available_coins, wallet, CAmount(0.025 * COIN), CFeeRate(0), 144, false, 0, true);
    1326                 :             :                 }
    1327                 :           1 :                 return available_coins;
    1328                 :           0 :             },
    1329         [ +  - ]:           1 :             m_node);
    1330                 :             : 
    1331   [ +  -  +  -  :           2 :         BOOST_CHECK(has_coin(result->GetInputSet(), CAmount(0.0625 * COIN)));
             +  -  +  - ]
    1332   [ +  -  +  -  :           2 :         BOOST_CHECK(has_coin(result->GetInputSet(), CAmount(0.025 * COIN)));
             +  -  +  - ]
    1333   [ +  -  +  - ]:           1 :         BOOST_CHECK_LE(result->GetWeight(), max_weight);
    1334                 :           0 :     }
    1335                 :             : 
    1336                 :           1 :     {
    1337                 :             :         // Scenario 3:
    1338                 :             : 
    1339                 :             :         // The actor starts with 1515x 0.033 BTC (49.995 BTC total) unspent outputs
    1340                 :             :         // No results should be returned, because the transaction would be too large
    1341                 :             : 
    1342                 :             :         // Perform selection
    1343                 :           1 :         const auto result = select_coins(
    1344         [ +  - ]:           2 :             target, cs_params, cc, [&](CWallet& wallet) {
    1345                 :           1 :                 CoinsResult available_coins;
    1346         [ +  + ]:        1516 :                 for (int j = 0; j < 1515; ++j) {
    1347         [ +  - ]:        1515 :                     add_coin(available_coins, wallet, CAmount(0.033 * COIN), CFeeRate(0), 144, false, 0, true);
    1348                 :             :                 }
    1349                 :           1 :                 return available_coins;
    1350                 :           0 :             },
    1351         [ +  - ]:           1 :             m_node);
    1352                 :             : 
    1353                 :             :         // No results
    1354                 :             :         // 1515 inputs * 68 bytes = 103,020 bytes
    1355                 :             :         // 103,020 bytes * 4 = 412,080 weight, which is above the MAX_STANDARD_TX_WEIGHT of 400,000
    1356   [ +  -  +  - ]:           2 :         BOOST_CHECK(!result);
    1357                 :           1 :     }
    1358                 :           1 : }
    1359                 :             : 
    1360   [ +  -  +  -  :           7 : BOOST_AUTO_TEST_CASE(SelectCoins_effective_value_test)
          +  -  +  -  -  
          +  +  -  +  -  
          +  -  +  -  +  
          -  +  -  -  +  
          +  -  +  -  +  
          -  +  -  +  -  
          +  -  -  +  +  
          -  +  -  +  -  
          +  -  +  -  +  
          -  +  -  -  +  
          +  -  +  -  +  
          -  +  -  +  -  
          +  -  -  +  +  
                      - ]
    1361                 :             : {
    1362                 :             :     // Test that the effective value is used to check whether preset inputs provide sufficient funds when subtract_fee_outputs is not used.
    1363                 :             :     // This test creates a coin whose value is higher than the target but whose effective value is lower than the target.
    1364                 :             :     // The coin is selected using coin control, with m_allow_other_inputs = false. SelectCoins should fail due to insufficient funds.
    1365                 :             : 
    1366         [ +  - ]:           1 :     std::unique_ptr<CWallet> wallet = NewWallet(m_node);
    1367                 :             : 
    1368         [ +  - ]:           1 :     CoinsResult available_coins;
    1369                 :           1 :     {
    1370   [ +  -  +  - ]:           1 :         std::unique_ptr<CWallet> dummyWallet = NewWallet(m_node, /*wallet_name=*/"dummy");
    1371         [ +  - ]:           1 :         add_coin(available_coins, *dummyWallet, 100000); // 0.001 BTC
    1372                 :           0 :     }
    1373                 :             : 
    1374                 :           1 :     CAmount target{99900}; // 0.000999 BTC
    1375                 :             : 
    1376                 :           1 :     FastRandomContext rand;
    1377         [ +  - ]:           1 :     CoinSelectionParams cs_params{
    1378                 :             :         rand,
    1379                 :             :         /*change_output_size=*/34,
    1380                 :             :         /*change_spend_size=*/148,
    1381                 :             :         /*min_change_target=*/1000,
    1382                 :           1 :         /*effective_feerate=*/CFeeRate(3000),
    1383                 :           1 :         /*long_term_feerate=*/CFeeRate(1000),
    1384                 :           1 :         /*discard_feerate=*/CFeeRate(1000),
    1385                 :             :         /*tx_noinputs_size=*/0,
    1386                 :             :         /*avoid_partial=*/false,
    1387         [ +  - ]:           1 :     };
    1388         [ +  - ]:           1 :     CCoinControl cc;
    1389                 :           1 :     cc.m_allow_other_inputs = false;
    1390         [ +  - ]:           2 :     COutput output = available_coins.All().at(0);
    1391         [ +  - ]:           1 :     cc.SetInputWeight(output.outpoint, 148);
    1392   [ +  -  +  - ]:           1 :     cc.Select(output.outpoint).SetTxOut(output.txout);
    1393                 :             : 
    1394         [ +  - ]:           1 :     LOCK(wallet->cs_wallet);
    1395   [ +  -  +  -  :           1 :     const auto preset_inputs = *Assert(FetchSelectedInputs(*wallet, cc, cs_params));
                   +  - ]
    1396   [ +  -  +  -  :           3 :     available_coins.Erase({available_coins.coins[OutputType::BECH32].begin()->outpoint});
             +  -  +  - ]
    1397                 :             : 
    1398         [ +  - ]:           1 :     const auto result = SelectCoins(*wallet, available_coins, preset_inputs, target, cc, cs_params);
    1399   [ +  -  +  - ]:           2 :     BOOST_CHECK(!result);
    1400   [ +  -  +  - ]:           3 : }
    1401                 :             : 
    1402   [ +  -  +  -  :           7 : BOOST_FIXTURE_TEST_CASE(wallet_coinsresult_test, BasicTestingSetup)
          +  -  +  -  -  
          +  +  -  +  -  
          +  -  +  -  +  
          -  +  -  -  +  
          +  -  +  -  +  
          -  +  -  +  -  
          +  -  -  +  +  
          -  +  -  +  -  
          +  -  +  -  +  
          -  +  -  -  +  
          +  -  +  -  +  
          -  +  -  +  -  
          +  -  -  +  +  
                      - ]
    1403                 :             : {
    1404                 :             :     // Test case to verify CoinsResult object sanity.
    1405         [ +  - ]:           1 :     CoinsResult available_coins;
    1406                 :           1 :     {
    1407   [ +  -  +  - ]:           1 :         std::unique_ptr<CWallet> dummyWallet = NewWallet(m_node, /*wallet_name=*/"dummy");
    1408                 :             : 
    1409                 :             :         // Add some coins to 'available_coins'
    1410         [ +  + ]:          11 :         for (int i=0; i<10; i++) {
    1411         [ +  - ]:          10 :             add_coin(available_coins, *dummyWallet, 1 * COIN);
    1412                 :             :         }
    1413                 :           0 :     }
    1414                 :             : 
    1415                 :           1 :     {
    1416                 :             :         // First test case, check that 'CoinsResult::Erase' function works as expected.
    1417                 :             :         // By trying to erase two elements from the 'available_coins' object.
    1418         [ +  - ]:           1 :         std::unordered_set<COutPoint, SaltedOutpointHasher> outs_to_remove;
    1419         [ +  - ]:           1 :         const auto& coins = available_coins.All();
    1420         [ +  + ]:           3 :         for (int i = 0; i < 2; i++) {
    1421         [ +  - ]:           2 :             outs_to_remove.emplace(coins[i].outpoint);
    1422                 :             :         }
    1423         [ +  - ]:           1 :         available_coins.Erase(outs_to_remove);
    1424                 :             : 
    1425                 :             :         // Check that the elements were actually removed.
    1426         [ +  - ]:           1 :         const auto& updated_coins = available_coins.All();
    1427         [ +  + ]:           3 :         for (const auto& out: outs_to_remove) {
    1428                 :          18 :             auto it = std::find_if(updated_coins.begin(), updated_coins.end(), [&out](const COutput &coin) {
    1429         [ +  - ]:          16 :                 return coin.outpoint == out;
    1430                 :             :             });
    1431   [ +  -  +  - ]:           4 :             BOOST_CHECK(it == updated_coins.end());
    1432                 :             :         }
    1433                 :             :         // And verify that no extra element were removed
    1434   [ +  -  +  -  :           1 :         BOOST_CHECK_EQUAL(available_coins.Size(), 8);
                   +  - ]
    1435                 :           1 :     }
    1436                 :           1 : }
    1437                 :             : 
    1438                 :             : BOOST_AUTO_TEST_SUITE_END()
    1439                 :             : } // namespace wallet
        

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