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diff --git a/src/wallet/test/coinselector_tests.cpp b/src/wallet/test/coinselector_tests.cpp
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+// Copyright (c) 2017 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include "wallet/wallet.h"
+#include "wallet/coinselection.h"
+#include "wallet/coincontrol.h"
+#include "amount.h"
+#include "primitives/transaction.h"
+#include "random.h"
+#include "test/test_bitcoin.h"
+#include "wallet/test/wallet_test_fixture.h"
+
+#include <boost/test/unit_test.hpp>
+#include <random>
+
+BOOST_FIXTURE_TEST_SUITE(coin_selection_tests, WalletTestingSetup)
+
+// how many times to run all the tests to have a chance to catch errors that only show up with particular random shuffles
+#define RUN_TESTS 100
+
+// some tests fail 1% of the time due to bad luck.
+// we repeat those tests this many times and only complain if all iterations of the test fail
+#define RANDOM_REPEATS 5
+
+std::vector<std::unique_ptr<CWalletTx>> wtxn;
+
+typedef std::set<CInputCoin> CoinSet;
+
+static std::vector<COutput> vCoins;
+static CWallet testWallet("dummy", CWalletDBWrapper::CreateDummy());
+static CAmount balance = 0;
+
+CoinEligibilityFilter filter_standard(1, 6, 0);
+CoinEligibilityFilter filter_confirmed(1, 1, 0);
+CoinEligibilityFilter filter_standard_extra(6, 6, 0);
+CoinSelectionParams coin_selection_params(false, 0, 0, CFeeRate(0), 0);
+
+static void add_coin(const CAmount& nValue, int nInput, std::vector<CInputCoin>& set)
+{
+ CMutableTransaction tx;
+ tx.vout.resize(nInput + 1);
+ tx.vout[nInput].nValue = nValue;
+ set.emplace_back(MakeTransactionRef(tx), nInput);
+}
+
+static void add_coin(const CAmount& nValue, int nInput, CoinSet& set)
+{
+ CMutableTransaction tx;
+ tx.vout.resize(nInput + 1);
+ tx.vout[nInput].nValue = nValue;
+ set.emplace(MakeTransactionRef(tx), nInput);
+}
+
+static void add_coin(const CAmount& nValue, int nAge = 6*24, bool fIsFromMe = false, int nInput=0)
+{
+ balance += nValue;
+ static int nextLockTime = 0;
+ CMutableTransaction tx;
+ tx.nLockTime = nextLockTime++; // so all transactions get different hashes
+ tx.vout.resize(nInput + 1);
+ tx.vout[nInput].nValue = nValue;
+ if (fIsFromMe) {
+ // IsFromMe() returns (GetDebit() > 0), and GetDebit() is 0 if vin.empty(),
+ // so stop vin being empty, and cache a non-zero Debit to fake out IsFromMe()
+ tx.vin.resize(1);
+ }
+ std::unique_ptr<CWalletTx> wtx(new CWalletTx(&testWallet, MakeTransactionRef(std::move(tx))));
+ if (fIsFromMe)
+ {
+ wtx->fDebitCached = true;
+ wtx->nDebitCached = 1;
+ }
+ COutput output(wtx.get(), nInput, nAge, true /* spendable */, true /* solvable */, true /* safe */);
+ vCoins.push_back(output);
+ testWallet.AddToWallet(*wtx.get());
+ wtxn.emplace_back(std::move(wtx));
+}
+
+static void empty_wallet(void)
+{
+ vCoins.clear();
+ wtxn.clear();
+ balance = 0;
+}
+
+static bool equal_sets(CoinSet a, CoinSet b)
+{
+ std::pair<CoinSet::iterator, CoinSet::iterator> ret = mismatch(a.begin(), a.end(), b.begin());
+ return ret.first == a.end() && ret.second == b.end();
+}
+
+static CAmount make_hard_case(int utxos, std::vector<CInputCoin>& utxo_pool)
+{
+ utxo_pool.clear();
+ CAmount target = 0;
+ for (int i = 0; i < utxos; ++i) {
+ target += (CAmount)1 << (utxos+i);
+ add_coin((CAmount)1 << (utxos+i), 2*i, utxo_pool);
+ add_coin(((CAmount)1 << (utxos+i)) + ((CAmount)1 << (utxos-1-i)), 2*i + 1, utxo_pool);
+ }
+ return target;
+}
+
+// Branch and bound coin selection tests
+BOOST_AUTO_TEST_CASE(bnb_search_test)
+{
+
+ LOCK(testWallet.cs_wallet);
+
+ // Setup
+ std::vector<CInputCoin> utxo_pool;
+ CoinSet selection;
+ CoinSet actual_selection;
+ CAmount value_ret = 0;
+ CAmount not_input_fees = 0;
+
+ /////////////////////////
+ // Known Outcome tests //
+ /////////////////////////
+ BOOST_TEST_MESSAGE("Testing known outcomes");
+
+ // Empty utxo pool
+ BOOST_CHECK(!SelectCoinsBnB(utxo_pool, 1 * CENT, 0.5 * CENT, selection, value_ret, not_input_fees));
+ selection.clear();
+
+ // Add utxos
+ add_coin(1 * CENT, 1, utxo_pool);
+ add_coin(2 * CENT, 2, utxo_pool);
+ add_coin(3 * CENT, 3, utxo_pool);
+ add_coin(4 * CENT, 4, utxo_pool);
+
+ // Select 1 Cent
+ add_coin(1 * CENT, 1, actual_selection);
+ BOOST_CHECK(SelectCoinsBnB(utxo_pool, 1 * CENT, 0.5 * CENT, selection, value_ret, not_input_fees));
+ BOOST_CHECK(equal_sets(selection, actual_selection));
+ actual_selection.clear();
+ selection.clear();
+
+ // Select 2 Cent
+ add_coin(2 * CENT, 2, actual_selection);
+ BOOST_CHECK(SelectCoinsBnB(utxo_pool, 2 * CENT, 0.5 * CENT, selection, value_ret, not_input_fees));
+ BOOST_CHECK(equal_sets(selection, actual_selection));
+ actual_selection.clear();
+ selection.clear();
+
+ // Select 5 Cent
+ add_coin(3 * CENT, 3, actual_selection);
+ add_coin(2 * CENT, 2, actual_selection);
+ BOOST_CHECK(SelectCoinsBnB(utxo_pool, 5 * CENT, 0.5 * CENT, selection, value_ret, not_input_fees));
+ BOOST_CHECK(equal_sets(selection, actual_selection));
+ actual_selection.clear();
+ selection.clear();
+
+ // Select 11 Cent, not possible
+ BOOST_CHECK(!SelectCoinsBnB(utxo_pool, 11 * CENT, 0.5 * CENT, selection, value_ret, not_input_fees));
+ actual_selection.clear();
+ selection.clear();
+
+ // Select 10 Cent
+ add_coin(5 * CENT, 5, utxo_pool);
+ add_coin(4 * CENT, 4, actual_selection);
+ add_coin(3 * CENT, 3, actual_selection);
+ add_coin(2 * CENT, 2, actual_selection);
+ add_coin(1 * CENT, 1, actual_selection);
+ BOOST_CHECK(SelectCoinsBnB(utxo_pool, 10 * CENT, 0.5 * CENT, selection, value_ret, not_input_fees));
+ BOOST_CHECK(equal_sets(selection, actual_selection));
+ actual_selection.clear();
+ selection.clear();
+
+ // Negative effective value
+ // Select 10 Cent but have 1 Cent not be possible because too small
+ add_coin(5 * CENT, 5, actual_selection);
+ add_coin(3 * CENT, 3, actual_selection);
+ add_coin(2 * CENT, 2, actual_selection);
+ BOOST_CHECK(SelectCoinsBnB(utxo_pool, 10 * CENT, 5000, selection, value_ret, not_input_fees));
+
+ // Select 0.25 Cent, not possible
+ BOOST_CHECK(!SelectCoinsBnB(utxo_pool, 0.25 * CENT, 0.5 * CENT, selection, value_ret, not_input_fees));
+ actual_selection.clear();
+ selection.clear();
+
+ // Iteration exhaustion test
+ CAmount target = make_hard_case(17, utxo_pool);
+ BOOST_CHECK(!SelectCoinsBnB(utxo_pool, target, 0, selection, value_ret, not_input_fees)); // Should exhaust
+ target = make_hard_case(14, utxo_pool);
+ BOOST_CHECK(SelectCoinsBnB(utxo_pool, target, 0, selection, value_ret, not_input_fees)); // Should not exhaust
+
+ // Test same value early bailout optimization
+ add_coin(7 * CENT, 7, actual_selection);
+ add_coin(7 * CENT, 7, actual_selection);
+ add_coin(7 * CENT, 7, actual_selection);
+ add_coin(7 * CENT, 7, actual_selection);
+ add_coin(2 * CENT, 7, actual_selection);
+ add_coin(7 * CENT, 7, utxo_pool);
+ add_coin(7 * CENT, 7, utxo_pool);
+ add_coin(7 * CENT, 7, utxo_pool);
+ add_coin(7 * CENT, 7, utxo_pool);
+ add_coin(2 * CENT, 7, utxo_pool);
+ for (int i = 0; i < 50000; ++i) {
+ add_coin(5 * CENT, 7, utxo_pool);
+ }
+ BOOST_CHECK(SelectCoinsBnB(utxo_pool, 30 * CENT, 5000, selection, value_ret, not_input_fees));
+
+ ////////////////////
+ // Behavior tests //
+ ////////////////////
+ // Select 1 Cent with pool of only greater than 5 Cent
+ utxo_pool.clear();
+ for (int i = 5; i <= 20; ++i) {
+ add_coin(i * CENT, i, utxo_pool);
+ }
+ // Run 100 times, to make sure it is never finding a solution
+ for (int i = 0; i < 100; ++i) {
+ BOOST_CHECK(!SelectCoinsBnB(utxo_pool, 1 * CENT, 2 * CENT, selection, value_ret, not_input_fees));
+ }
+
+ // Make sure that effective value is working in SelectCoinsMinConf when BnB is used
+ CoinSelectionParams coin_selection_params_bnb(true, 0, 0, CFeeRate(3000), 0);
+ CoinSet setCoinsRet;
+ CAmount nValueRet;
+ bool bnb_used;
+ empty_wallet();
+ add_coin(1);
+ vCoins.at(0).nInputBytes = 40; // Make sure that it has a negative effective value. The next check should assert if this somehow got through. Otherwise it will fail
+ BOOST_CHECK(!testWallet.SelectCoinsMinConf( 1 * CENT, filter_standard, vCoins, setCoinsRet, nValueRet, coin_selection_params_bnb, bnb_used));
+
+ // Make sure that we aren't using BnB when there are preset inputs
+ empty_wallet();
+ add_coin(5 * CENT);
+ add_coin(3 * CENT);
+ add_coin(2 * CENT);
+ CCoinControl coin_control;
+ coin_control.fAllowOtherInputs = true;
+ coin_control.Select(COutPoint(vCoins.at(0).tx->GetHash(), vCoins.at(0).i));
+ BOOST_CHECK(testWallet.SelectCoins(vCoins, 10 * CENT, setCoinsRet, nValueRet, coin_control, coin_selection_params_bnb, bnb_used));
+ BOOST_CHECK(!bnb_used);
+ BOOST_CHECK(!coin_selection_params_bnb.use_bnb);
+}
+
+BOOST_AUTO_TEST_CASE(knapsack_solver_test)
+{
+ CoinSet setCoinsRet, setCoinsRet2;
+ CAmount nValueRet;
+ bool bnb_used;
+
+ LOCK(testWallet.cs_wallet);
+
+ // test multiple times to allow for differences in the shuffle order
+ for (int i = 0; i < RUN_TESTS; i++)
+ {
+ empty_wallet();
+
+ // with an empty wallet we can't even pay one cent
+ BOOST_CHECK(!testWallet.SelectCoinsMinConf( 1 * CENT, filter_standard, vCoins, setCoinsRet, nValueRet, coin_selection_params, bnb_used));
+
+ add_coin(1*CENT, 4); // add a new 1 cent coin
+
+ // with a new 1 cent coin, we still can't find a mature 1 cent
+ BOOST_CHECK(!testWallet.SelectCoinsMinConf( 1 * CENT, filter_standard, vCoins, setCoinsRet, nValueRet, coin_selection_params, bnb_used));
+
+ // but we can find a new 1 cent
+ BOOST_CHECK( testWallet.SelectCoinsMinConf( 1 * CENT, filter_confirmed, vCoins, setCoinsRet, nValueRet, coin_selection_params, bnb_used));
+ BOOST_CHECK_EQUAL(nValueRet, 1 * CENT);
+
+ add_coin(2*CENT); // add a mature 2 cent coin
+
+ // we can't make 3 cents of mature coins
+ BOOST_CHECK(!testWallet.SelectCoinsMinConf( 3 * CENT, filter_standard, vCoins, setCoinsRet, nValueRet, coin_selection_params, bnb_used));
+
+ // we can make 3 cents of new coins
+ BOOST_CHECK( testWallet.SelectCoinsMinConf( 3 * CENT, filter_confirmed, vCoins, setCoinsRet, nValueRet, coin_selection_params, bnb_used));
+ BOOST_CHECK_EQUAL(nValueRet, 3 * CENT);
+
+ add_coin(5*CENT); // add a mature 5 cent coin,
+ add_coin(10*CENT, 3, true); // a new 10 cent coin sent from one of our own addresses
+ add_coin(20*CENT); // and a mature 20 cent coin
+
+ // now we have new: 1+10=11 (of which 10 was self-sent), and mature: 2+5+20=27. total = 38
+
+ // we can't make 38 cents only if we disallow new coins:
+ BOOST_CHECK(!testWallet.SelectCoinsMinConf(38 * CENT, filter_standard, vCoins, setCoinsRet, nValueRet, coin_selection_params, bnb_used));
+ // we can't even make 37 cents if we don't allow new coins even if they're from us
+ BOOST_CHECK(!testWallet.SelectCoinsMinConf(38 * CENT, filter_standard_extra, vCoins, setCoinsRet, nValueRet, coin_selection_params, bnb_used));
+ // but we can make 37 cents if we accept new coins from ourself
+ BOOST_CHECK( testWallet.SelectCoinsMinConf(37 * CENT, filter_standard, vCoins, setCoinsRet, nValueRet, coin_selection_params, bnb_used));
+ BOOST_CHECK_EQUAL(nValueRet, 37 * CENT);
+ // and we can make 38 cents if we accept all new coins
+ BOOST_CHECK( testWallet.SelectCoinsMinConf(38 * CENT, filter_confirmed, vCoins, setCoinsRet, nValueRet, coin_selection_params, bnb_used));
+ BOOST_CHECK_EQUAL(nValueRet, 38 * CENT);
+
+ // try making 34 cents from 1,2,5,10,20 - we can't do it exactly
+ BOOST_CHECK( testWallet.SelectCoinsMinConf(34 * CENT, filter_confirmed, vCoins, setCoinsRet, nValueRet, coin_selection_params, bnb_used));
+ BOOST_CHECK_EQUAL(nValueRet, 35 * CENT); // but 35 cents is closest
+ BOOST_CHECK_EQUAL(setCoinsRet.size(), 3U); // the best should be 20+10+5. it's incredibly unlikely the 1 or 2 got included (but possible)
+
+ // when we try making 7 cents, the smaller coins (1,2,5) are enough. We should see just 2+5
+ BOOST_CHECK( testWallet.SelectCoinsMinConf( 7 * CENT, filter_confirmed, vCoins, setCoinsRet, nValueRet, coin_selection_params, bnb_used));
+ BOOST_CHECK_EQUAL(nValueRet, 7 * CENT);
+ BOOST_CHECK_EQUAL(setCoinsRet.size(), 2U);
+
+ // when we try making 8 cents, the smaller coins (1,2,5) are exactly enough.
+ BOOST_CHECK( testWallet.SelectCoinsMinConf( 8 * CENT, filter_confirmed, vCoins, setCoinsRet, nValueRet, coin_selection_params, bnb_used));
+ BOOST_CHECK(nValueRet == 8 * CENT);
+ BOOST_CHECK_EQUAL(setCoinsRet.size(), 3U);
+
+ // when we try making 9 cents, no subset of smaller coins is enough, and we get the next bigger coin (10)
+ BOOST_CHECK( testWallet.SelectCoinsMinConf( 9 * CENT, filter_confirmed, vCoins, setCoinsRet, nValueRet, coin_selection_params, bnb_used));
+ BOOST_CHECK_EQUAL(nValueRet, 10 * CENT);
+ BOOST_CHECK_EQUAL(setCoinsRet.size(), 1U);
+
+ // now clear out the wallet and start again to test choosing between subsets of smaller coins and the next biggest coin
+ empty_wallet();
+
+ add_coin( 6*CENT);
+ add_coin( 7*CENT);
+ add_coin( 8*CENT);
+ add_coin(20*CENT);
+ add_coin(30*CENT); // now we have 6+7+8+20+30 = 71 cents total
+
+ // check that we have 71 and not 72
+ BOOST_CHECK( testWallet.SelectCoinsMinConf(71 * CENT, filter_confirmed, vCoins, setCoinsRet, nValueRet, coin_selection_params, bnb_used));
+ BOOST_CHECK(!testWallet.SelectCoinsMinConf(72 * CENT, filter_confirmed, vCoins, setCoinsRet, nValueRet, coin_selection_params, bnb_used));
+
+ // 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
+ BOOST_CHECK( testWallet.SelectCoinsMinConf(16 * CENT, filter_confirmed, vCoins, setCoinsRet, nValueRet, coin_selection_params, bnb_used));
+ BOOST_CHECK_EQUAL(nValueRet, 20 * CENT); // we should get 20 in one coin
+ BOOST_CHECK_EQUAL(setCoinsRet.size(), 1U);
+
+ add_coin( 5*CENT); // now we have 5+6+7+8+20+30 = 75 cents total
+
+ // 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
+ BOOST_CHECK( testWallet.SelectCoinsMinConf(16 * CENT, filter_confirmed, vCoins, setCoinsRet, nValueRet, coin_selection_params, bnb_used));
+ BOOST_CHECK_EQUAL(nValueRet, 18 * CENT); // we should get 18 in 3 coins
+ BOOST_CHECK_EQUAL(setCoinsRet.size(), 3U);
+
+ add_coin( 18*CENT); // now we have 5+6+7+8+18+20+30
+
+ // 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
+ BOOST_CHECK( testWallet.SelectCoinsMinConf(16 * CENT, filter_confirmed, vCoins, setCoinsRet, nValueRet, coin_selection_params, bnb_used));
+ BOOST_CHECK_EQUAL(nValueRet, 18 * CENT); // we should get 18 in 1 coin
+ BOOST_CHECK_EQUAL(setCoinsRet.size(), 1U); // because in the event of a tie, the biggest coin wins
+
+ // now try making 11 cents. we should get 5+6
+ BOOST_CHECK( testWallet.SelectCoinsMinConf(11 * CENT, filter_confirmed, vCoins, setCoinsRet, nValueRet, coin_selection_params, bnb_used));
+ BOOST_CHECK_EQUAL(nValueRet, 11 * CENT);
+ BOOST_CHECK_EQUAL(setCoinsRet.size(), 2U);
+
+ // check that the smallest bigger coin is used
+ add_coin( 1*COIN);
+ add_coin( 2*COIN);
+ add_coin( 3*COIN);
+ add_coin( 4*COIN); // now we have 5+6+7+8+18+20+30+100+200+300+400 = 1094 cents
+ BOOST_CHECK( testWallet.SelectCoinsMinConf(95 * CENT, filter_confirmed, vCoins, setCoinsRet, nValueRet, coin_selection_params, bnb_used));
+ BOOST_CHECK_EQUAL(nValueRet, 1 * COIN); // we should get 1 BTC in 1 coin
+ BOOST_CHECK_EQUAL(setCoinsRet.size(), 1U);
+
+ BOOST_CHECK( testWallet.SelectCoinsMinConf(195 * CENT, filter_confirmed, vCoins, setCoinsRet, nValueRet, coin_selection_params, bnb_used));
+ BOOST_CHECK_EQUAL(nValueRet, 2 * COIN); // we should get 2 BTC in 1 coin
+ BOOST_CHECK_EQUAL(setCoinsRet.size(), 1U);
+
+ // empty the wallet and start again, now with fractions of a cent, to test small change avoidance
+
+ empty_wallet();
+ add_coin(MIN_CHANGE * 1 / 10);
+ add_coin(MIN_CHANGE * 2 / 10);
+ add_coin(MIN_CHANGE * 3 / 10);
+ add_coin(MIN_CHANGE * 4 / 10);
+ add_coin(MIN_CHANGE * 5 / 10);
+
+ // try making 1 * MIN_CHANGE from the 1.5 * MIN_CHANGE
+ // we'll get change smaller than MIN_CHANGE whatever happens, so can expect MIN_CHANGE exactly
+ BOOST_CHECK( testWallet.SelectCoinsMinConf(MIN_CHANGE, filter_confirmed, vCoins, setCoinsRet, nValueRet, coin_selection_params, bnb_used));
+ BOOST_CHECK_EQUAL(nValueRet, MIN_CHANGE);
+
+ // but if we add a bigger coin, small change is avoided
+ add_coin(1111*MIN_CHANGE);
+
+ // try making 1 from 0.1 + 0.2 + 0.3 + 0.4 + 0.5 + 1111 = 1112.5
+ BOOST_CHECK( testWallet.SelectCoinsMinConf(1 * MIN_CHANGE, filter_confirmed, vCoins, setCoinsRet, nValueRet, coin_selection_params, bnb_used));
+ BOOST_CHECK_EQUAL(nValueRet, 1 * MIN_CHANGE); // we should get the exact amount
+
+ // if we add more small coins:
+ add_coin(MIN_CHANGE * 6 / 10);
+ add_coin(MIN_CHANGE * 7 / 10);
+
+ // and try again to make 1.0 * MIN_CHANGE
+ BOOST_CHECK( testWallet.SelectCoinsMinConf(1 * MIN_CHANGE, filter_confirmed, vCoins, setCoinsRet, nValueRet, coin_selection_params, bnb_used));
+ BOOST_CHECK_EQUAL(nValueRet, 1 * MIN_CHANGE); // we should get the exact amount
+
+ // run the 'mtgox' test (see http://blockexplorer.com/tx/29a3efd3ef04f9153d47a990bd7b048a4b2d213daaa5fb8ed670fb85f13bdbcf)
+ // they tried to consolidate 10 50k coins into one 500k coin, and ended up with 50k in change
+ empty_wallet();
+ for (int j = 0; j < 20; j++)
+ add_coin(50000 * COIN);
+
+ BOOST_CHECK( testWallet.SelectCoinsMinConf(500000 * COIN, filter_confirmed, vCoins, setCoinsRet, nValueRet, coin_selection_params, bnb_used));
+ BOOST_CHECK_EQUAL(nValueRet, 500000 * COIN); // we should get the exact amount
+ BOOST_CHECK_EQUAL(setCoinsRet.size(), 10U); // in ten coins
+
+ // if there's not enough in the smaller coins to make at least 1 * MIN_CHANGE change (0.5+0.6+0.7 < 1.0+1.0),
+ // we need to try finding an exact subset anyway
+
+ // sometimes it will fail, and so we use the next biggest coin:
+ empty_wallet();
+ add_coin(MIN_CHANGE * 5 / 10);
+ add_coin(MIN_CHANGE * 6 / 10);
+ add_coin(MIN_CHANGE * 7 / 10);
+ add_coin(1111 * MIN_CHANGE);
+ BOOST_CHECK( testWallet.SelectCoinsMinConf(1 * MIN_CHANGE, filter_confirmed, vCoins, setCoinsRet, nValueRet, coin_selection_params, bnb_used));
+ BOOST_CHECK_EQUAL(nValueRet, 1111 * MIN_CHANGE); // we get the bigger coin
+ BOOST_CHECK_EQUAL(setCoinsRet.size(), 1U);
+
+ // but sometimes it's possible, and we use an exact subset (0.4 + 0.6 = 1.0)
+ empty_wallet();
+ add_coin(MIN_CHANGE * 4 / 10);
+ add_coin(MIN_CHANGE * 6 / 10);
+ add_coin(MIN_CHANGE * 8 / 10);
+ add_coin(1111 * MIN_CHANGE);
+ BOOST_CHECK( testWallet.SelectCoinsMinConf(MIN_CHANGE, filter_confirmed, vCoins, setCoinsRet, nValueRet, coin_selection_params, bnb_used));
+ BOOST_CHECK_EQUAL(nValueRet, MIN_CHANGE); // we should get the exact amount
+ BOOST_CHECK_EQUAL(setCoinsRet.size(), 2U); // in two coins 0.4+0.6
+
+ // test avoiding small change
+ empty_wallet();
+ add_coin(MIN_CHANGE * 5 / 100);
+ add_coin(MIN_CHANGE * 1);
+ add_coin(MIN_CHANGE * 100);
+
+ // trying to make 100.01 from these three coins
+ BOOST_CHECK(testWallet.SelectCoinsMinConf(MIN_CHANGE * 10001 / 100, filter_confirmed, vCoins, setCoinsRet, nValueRet, coin_selection_params, bnb_used));
+ BOOST_CHECK_EQUAL(nValueRet, MIN_CHANGE * 10105 / 100); // we should get all coins
+ BOOST_CHECK_EQUAL(setCoinsRet.size(), 3U);
+
+ // but if we try to make 99.9, we should take the bigger of the two small coins to avoid small change
+ BOOST_CHECK(testWallet.SelectCoinsMinConf(MIN_CHANGE * 9990 / 100, filter_confirmed, vCoins, setCoinsRet, nValueRet, coin_selection_params, bnb_used));
+ BOOST_CHECK_EQUAL(nValueRet, 101 * MIN_CHANGE);
+ BOOST_CHECK_EQUAL(setCoinsRet.size(), 2U);
+
+ // test with many inputs
+ for (CAmount amt=1500; amt < COIN; amt*=10) {
+ empty_wallet();
+ // Create 676 inputs (= (old MAX_STANDARD_TX_SIZE == 100000) / 148 bytes per input)
+ for (uint16_t j = 0; j < 676; j++)
+ add_coin(amt);
+ BOOST_CHECK(testWallet.SelectCoinsMinConf(2000, filter_confirmed, vCoins, setCoinsRet, nValueRet, coin_selection_params, bnb_used));
+ if (amt - 2000 < MIN_CHANGE) {
+ // needs more than one input:
+ uint16_t returnSize = std::ceil((2000.0 + MIN_CHANGE)/amt);
+ CAmount returnValue = amt * returnSize;
+ BOOST_CHECK_EQUAL(nValueRet, returnValue);
+ BOOST_CHECK_EQUAL(setCoinsRet.size(), returnSize);
+ } else {
+ // one input is sufficient:
+ BOOST_CHECK_EQUAL(nValueRet, amt);
+ BOOST_CHECK_EQUAL(setCoinsRet.size(), 1U);
+ }
+ }
+
+ // test randomness
+ {
+ empty_wallet();
+ for (int i2 = 0; i2 < 100; i2++)
+ add_coin(COIN);
+
+ // picking 50 from 100 coins doesn't depend on the shuffle,
+ // but does depend on randomness in the stochastic approximation code
+ BOOST_CHECK(testWallet.SelectCoinsMinConf(50 * COIN, filter_standard, vCoins, setCoinsRet , nValueRet, coin_selection_params, bnb_used));
+ BOOST_CHECK(testWallet.SelectCoinsMinConf(50 * COIN, filter_standard, vCoins, setCoinsRet2, nValueRet, coin_selection_params, bnb_used));
+ BOOST_CHECK(!equal_sets(setCoinsRet, setCoinsRet2));
+
+ int fails = 0;
+ for (int j = 0; j < RANDOM_REPEATS; j++)
+ {
+ // selecting 1 from 100 identical coins depends on the shuffle; this test will fail 1% of the time
+ // run the test RANDOM_REPEATS times and only complain if all of them fail
+ BOOST_CHECK(testWallet.SelectCoinsMinConf(COIN, filter_standard, vCoins, setCoinsRet , nValueRet, coin_selection_params, bnb_used));
+ BOOST_CHECK(testWallet.SelectCoinsMinConf(COIN, filter_standard, vCoins, setCoinsRet2, nValueRet, coin_selection_params, bnb_used));
+ if (equal_sets(setCoinsRet, setCoinsRet2))
+ fails++;
+ }
+ BOOST_CHECK_NE(fails, RANDOM_REPEATS);
+
+ // add 75 cents in small change. not enough to make 90 cents,
+ // then try making 90 cents. there are multiple competing "smallest bigger" coins,
+ // one of which should be picked at random
+ add_coin(5 * CENT);
+ add_coin(10 * CENT);
+ add_coin(15 * CENT);
+ add_coin(20 * CENT);
+ add_coin(25 * CENT);
+
+ fails = 0;
+ for (int j = 0; j < RANDOM_REPEATS; j++)
+ {
+ // selecting 1 from 100 identical coins depends on the shuffle; this test will fail 1% of the time
+ // run the test RANDOM_REPEATS times and only complain if all of them fail
+ BOOST_CHECK(testWallet.SelectCoinsMinConf(90*CENT, filter_standard, vCoins, setCoinsRet , nValueRet, coin_selection_params, bnb_used));
+ BOOST_CHECK(testWallet.SelectCoinsMinConf(90*CENT, filter_standard, vCoins, setCoinsRet2, nValueRet, coin_selection_params, bnb_used));
+ if (equal_sets(setCoinsRet, setCoinsRet2))
+ fails++;
+ }
+ BOOST_CHECK_NE(fails, RANDOM_REPEATS);
+ }
+ }
+ empty_wallet();
+}
+
+BOOST_AUTO_TEST_CASE(ApproximateBestSubset)
+{
+ CoinSet setCoinsRet;
+ CAmount nValueRet;
+ bool bnb_used;
+
+ LOCK(testWallet.cs_wallet);
+
+ empty_wallet();
+
+ // Test vValue sort order
+ for (int i = 0; i < 1000; i++)
+ add_coin(1000 * COIN);
+ add_coin(3 * COIN);
+
+ BOOST_CHECK(testWallet.SelectCoinsMinConf(1003 * COIN, filter_standard, vCoins, setCoinsRet, nValueRet, coin_selection_params, bnb_used));
+ BOOST_CHECK_EQUAL(nValueRet, 1003 * COIN);
+ BOOST_CHECK_EQUAL(setCoinsRet.size(), 2U);
+
+ empty_wallet();
+}
+
+// Tests that with the ideal conditions, the coin selector will always be able to find a solution that can pay the target value
+BOOST_AUTO_TEST_CASE(SelectCoins_test)
+{
+ // Random generator stuff
+ std::default_random_engine generator;
+ std::exponential_distribution<double> distribution (100);
+ FastRandomContext rand;
+
+ // Output stuff
+ CAmount out_value = 0;
+ CoinSet out_set;
+ CAmount target = 0;
+ bool bnb_used;
+
+ // Run this test 100 times
+ for (int i = 0; i < 100; ++i)
+ {
+ // Reset
+ out_value = 0;
+ target = 0;
+ out_set.clear();
+ empty_wallet();
+
+ // Make a wallet with 1000 exponentially distributed random inputs
+ for (int j = 0; j < 1000; ++j)
+ {
+ add_coin((CAmount)(distribution(generator)*10000000));
+ }
+
+ // Generate a random fee rate in the range of 100 - 400
+ CFeeRate rate(rand.randrange(300) + 100);
+
+ // Generate a random target value between 1000 and wallet balance
+ target = rand.randrange(balance - 1000) + 1000;
+
+ // Perform selection
+ CoinSelectionParams coin_selection_params_knapsack(false, 34, 148, CFeeRate(0), 0);
+ CoinSelectionParams coin_selection_params_bnb(true, 34, 148, CFeeRate(0), 0);
+ BOOST_CHECK(testWallet.SelectCoinsMinConf(target, filter_standard, vCoins, out_set, out_value, coin_selection_params_bnb, bnb_used) ||
+ testWallet.SelectCoinsMinConf(target, filter_standard, vCoins, out_set, out_value, coin_selection_params_knapsack, bnb_used));
+ BOOST_CHECK_GE(out_value, target);
+ }
+}
+
+BOOST_AUTO_TEST_SUITE_END()