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Diffstat (limited to 'src/wallet/test/coinselector_tests.cpp')
-rw-r--r--src/wallet/test/coinselector_tests.cpp150
1 files changed, 115 insertions, 35 deletions
diff --git a/src/wallet/test/coinselector_tests.cpp b/src/wallet/test/coinselector_tests.cpp
index 3488ae3526..7b2169a5b6 100644
--- a/src/wallet/test/coinselector_tests.cpp
+++ b/src/wallet/test/coinselector_tests.cpp
@@ -49,12 +49,16 @@ static void add_coin(const CAmount& nValue, int nInput, std::vector<CInputCoin>&
set.emplace_back(MakeTransactionRef(tx), nInput);
}
-static void add_coin(const CAmount& nValue, int nInput, CoinSet& set)
+static void add_coin(const CAmount& nValue, int nInput, CoinSet& set, CAmount fee = 0, CAmount long_term_fee = 0)
{
CMutableTransaction tx;
tx.vout.resize(nInput + 1);
tx.vout[nInput].nValue = nValue;
- set.emplace(MakeTransactionRef(tx), nInput);
+ CInputCoin coin(MakeTransactionRef(tx), nInput);
+ coin.effective_value = nValue - fee;
+ coin.m_fee = fee;
+ coin.m_long_term_fee = long_term_fee;
+ set.insert(coin);
}
static void add_coin(CWallet& wallet, const CAmount& nValue, int nAge = 6*24, bool fIsFromMe = false, int nInput=0, bool spendable = false)
@@ -137,6 +141,13 @@ inline std::vector<OutputGroup>& GroupCoins(const std::vector<COutput>& coins)
return static_groups;
}
+inline std::vector<OutputGroup>& KnapsackGroupOutputs(const CoinEligibilityFilter& filter)
+{
+ static std::vector<OutputGroup> static_groups;
+ static_groups = testWallet.GroupOutputs(vCoins, coin_selection_params, filter, /* positive_only */false);
+ return static_groups;
+}
+
// Branch and bound coin selection tests
BOOST_AUTO_TEST_CASE(bnb_search_test)
{
@@ -281,14 +292,14 @@ BOOST_AUTO_TEST_CASE(bnb_search_test)
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.AttemptSelection( 1 * CENT, filter_standard, vCoins, setCoinsRet, nValueRet, coin_selection_params_bnb));
+ BOOST_CHECK(!SelectCoinsBnB(GroupCoins(vCoins), 1 * CENT, coin_selection_params_bnb.m_cost_of_change, setCoinsRet, nValueRet));
// Test fees subtracted from output:
empty_wallet();
add_coin(1 * CENT);
vCoins.at(0).nInputBytes = 40;
coin_selection_params_bnb.m_subtract_fee_outputs = true;
- BOOST_CHECK(testWallet.AttemptSelection( 1 * CENT, filter_standard, vCoins, setCoinsRet, nValueRet, coin_selection_params_bnb));
+ BOOST_CHECK(SelectCoinsBnB(GroupCoins(vCoins), 1 * CENT, coin_selection_params_bnb.m_cost_of_change, setCoinsRet, nValueRet));
BOOST_CHECK_EQUAL(nValueRet, 1 * CENT);
// Make sure that can use BnB when there are preset inputs
@@ -323,24 +334,24 @@ BOOST_AUTO_TEST_CASE(knapsack_solver_test)
empty_wallet();
// with an empty wallet we can't even pay one cent
- BOOST_CHECK(!testWallet.AttemptSelection( 1 * CENT, filter_standard, vCoins, setCoinsRet, nValueRet, coin_selection_params));
+ BOOST_CHECK(!KnapsackSolver(1 * CENT, KnapsackGroupOutputs(filter_standard), setCoinsRet, nValueRet));
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.AttemptSelection( 1 * CENT, filter_standard, vCoins, setCoinsRet, nValueRet, coin_selection_params));
+ BOOST_CHECK(!KnapsackSolver(1 * CENT, KnapsackGroupOutputs(filter_standard), setCoinsRet, nValueRet));
// but we can find a new 1 cent
- BOOST_CHECK( testWallet.AttemptSelection( 1 * CENT, filter_confirmed, vCoins, setCoinsRet, nValueRet, coin_selection_params));
+ BOOST_CHECK(KnapsackSolver(1 * CENT, KnapsackGroupOutputs(filter_confirmed), setCoinsRet, nValueRet));
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.AttemptSelection( 3 * CENT, filter_standard, vCoins, setCoinsRet, nValueRet, coin_selection_params));
+ BOOST_CHECK(!KnapsackSolver(3 * CENT, KnapsackGroupOutputs(filter_standard), setCoinsRet, nValueRet));
// we can make 3 cents of new coins
- BOOST_CHECK( testWallet.AttemptSelection( 3 * CENT, filter_confirmed, vCoins, setCoinsRet, nValueRet, coin_selection_params));
+ BOOST_CHECK(KnapsackSolver(3 * CENT, KnapsackGroupOutputs(filter_confirmed), setCoinsRet, nValueRet));
BOOST_CHECK_EQUAL(nValueRet, 3 * CENT);
add_coin(5*CENT); // add a mature 5 cent coin,
@@ -350,33 +361,33 @@ BOOST_AUTO_TEST_CASE(knapsack_solver_test)
// 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.AttemptSelection(38 * CENT, filter_standard, vCoins, setCoinsRet, nValueRet, coin_selection_params));
+ BOOST_CHECK(!KnapsackSolver(38 * CENT, KnapsackGroupOutputs(filter_standard), setCoinsRet, nValueRet));
// we can't even make 37 cents if we don't allow new coins even if they're from us
- BOOST_CHECK(!testWallet.AttemptSelection(38 * CENT, filter_standard_extra, vCoins, setCoinsRet, nValueRet, coin_selection_params));
+ BOOST_CHECK(!KnapsackSolver(38 * CENT, KnapsackGroupOutputs(filter_standard_extra), setCoinsRet, nValueRet));
// but we can make 37 cents if we accept new coins from ourself
- BOOST_CHECK( testWallet.AttemptSelection(37 * CENT, filter_standard, vCoins, setCoinsRet, nValueRet, coin_selection_params));
+ BOOST_CHECK(KnapsackSolver(37 * CENT, KnapsackGroupOutputs(filter_standard), setCoinsRet, nValueRet));
BOOST_CHECK_EQUAL(nValueRet, 37 * CENT);
// and we can make 38 cents if we accept all new coins
- BOOST_CHECK( testWallet.AttemptSelection(38 * CENT, filter_confirmed, vCoins, setCoinsRet, nValueRet, coin_selection_params));
+ BOOST_CHECK(KnapsackSolver(38 * CENT, KnapsackGroupOutputs(filter_confirmed), setCoinsRet, nValueRet));
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.AttemptSelection(34 * CENT, filter_confirmed, vCoins, setCoinsRet, nValueRet, coin_selection_params));
+ BOOST_CHECK(KnapsackSolver(34 * CENT, KnapsackGroupOutputs(filter_confirmed), setCoinsRet, nValueRet));
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.AttemptSelection( 7 * CENT, filter_confirmed, vCoins, setCoinsRet, nValueRet, coin_selection_params));
+ BOOST_CHECK(KnapsackSolver(7 * CENT, KnapsackGroupOutputs(filter_confirmed), setCoinsRet, nValueRet));
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.AttemptSelection( 8 * CENT, filter_confirmed, vCoins, setCoinsRet, nValueRet, coin_selection_params));
+ BOOST_CHECK(KnapsackSolver(8 * CENT, KnapsackGroupOutputs(filter_confirmed), setCoinsRet, nValueRet));
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.AttemptSelection( 9 * CENT, filter_confirmed, vCoins, setCoinsRet, nValueRet, coin_selection_params));
+ BOOST_CHECK(KnapsackSolver(9 * CENT, KnapsackGroupOutputs(filter_confirmed), setCoinsRet, nValueRet));
BOOST_CHECK_EQUAL(nValueRet, 10 * CENT);
BOOST_CHECK_EQUAL(setCoinsRet.size(), 1U);
@@ -390,30 +401,30 @@ BOOST_AUTO_TEST_CASE(knapsack_solver_test)
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.AttemptSelection(71 * CENT, filter_confirmed, vCoins, setCoinsRet, nValueRet, coin_selection_params));
- BOOST_CHECK(!testWallet.AttemptSelection(72 * CENT, filter_confirmed, vCoins, setCoinsRet, nValueRet, coin_selection_params));
+ BOOST_CHECK(KnapsackSolver(71 * CENT, KnapsackGroupOutputs(filter_confirmed), setCoinsRet, nValueRet));
+ BOOST_CHECK(!KnapsackSolver(72 * CENT, KnapsackGroupOutputs(filter_confirmed), setCoinsRet, nValueRet));
// 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.AttemptSelection(16 * CENT, filter_confirmed, vCoins, setCoinsRet, nValueRet, coin_selection_params));
+ BOOST_CHECK(KnapsackSolver(16 * CENT, KnapsackGroupOutputs(filter_confirmed), setCoinsRet, nValueRet));
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.AttemptSelection(16 * CENT, filter_confirmed, vCoins, setCoinsRet, nValueRet, coin_selection_params));
+ BOOST_CHECK(KnapsackSolver(16 * CENT, KnapsackGroupOutputs(filter_confirmed), setCoinsRet, nValueRet));
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.AttemptSelection(16 * CENT, filter_confirmed, vCoins, setCoinsRet, nValueRet, coin_selection_params));
+ BOOST_CHECK(KnapsackSolver(16 * CENT, KnapsackGroupOutputs(filter_confirmed), setCoinsRet, nValueRet));
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.AttemptSelection(11 * CENT, filter_confirmed, vCoins, setCoinsRet, nValueRet, coin_selection_params));
+ BOOST_CHECK(KnapsackSolver(11 * CENT, KnapsackGroupOutputs(filter_confirmed), setCoinsRet, nValueRet));
BOOST_CHECK_EQUAL(nValueRet, 11 * CENT);
BOOST_CHECK_EQUAL(setCoinsRet.size(), 2U);
@@ -422,11 +433,11 @@ BOOST_AUTO_TEST_CASE(knapsack_solver_test)
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.AttemptSelection(95 * CENT, filter_confirmed, vCoins, setCoinsRet, nValueRet, coin_selection_params));
+ BOOST_CHECK(KnapsackSolver(95 * CENT, KnapsackGroupOutputs(filter_confirmed), setCoinsRet, nValueRet));
BOOST_CHECK_EQUAL(nValueRet, 1 * COIN); // we should get 1 BTC in 1 coin
BOOST_CHECK_EQUAL(setCoinsRet.size(), 1U);
- BOOST_CHECK( testWallet.AttemptSelection(195 * CENT, filter_confirmed, vCoins, setCoinsRet, nValueRet, coin_selection_params));
+ BOOST_CHECK(KnapsackSolver(195 * CENT, KnapsackGroupOutputs(filter_confirmed), setCoinsRet, nValueRet));
BOOST_CHECK_EQUAL(nValueRet, 2 * COIN); // we should get 2 BTC in 1 coin
BOOST_CHECK_EQUAL(setCoinsRet.size(), 1U);
@@ -441,14 +452,14 @@ BOOST_AUTO_TEST_CASE(knapsack_solver_test)
// 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.AttemptSelection(MIN_CHANGE, filter_confirmed, vCoins, setCoinsRet, nValueRet, coin_selection_params));
+ BOOST_CHECK(KnapsackSolver(MIN_CHANGE, KnapsackGroupOutputs(filter_confirmed), setCoinsRet, nValueRet));
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.AttemptSelection(1 * MIN_CHANGE, filter_confirmed, vCoins, setCoinsRet, nValueRet, coin_selection_params));
+ BOOST_CHECK(KnapsackSolver(1 * MIN_CHANGE, KnapsackGroupOutputs(filter_confirmed), setCoinsRet, nValueRet));
BOOST_CHECK_EQUAL(nValueRet, 1 * MIN_CHANGE); // we should get the exact amount
// if we add more small coins:
@@ -456,7 +467,7 @@ BOOST_AUTO_TEST_CASE(knapsack_solver_test)
add_coin(MIN_CHANGE * 7 / 10);
// and try again to make 1.0 * MIN_CHANGE
- BOOST_CHECK( testWallet.AttemptSelection(1 * MIN_CHANGE, filter_confirmed, vCoins, setCoinsRet, nValueRet, coin_selection_params));
+ BOOST_CHECK(KnapsackSolver(1 * MIN_CHANGE, KnapsackGroupOutputs(filter_confirmed), setCoinsRet, nValueRet));
BOOST_CHECK_EQUAL(nValueRet, 1 * MIN_CHANGE); // we should get the exact amount
// run the 'mtgox' test (see https://blockexplorer.com/tx/29a3efd3ef04f9153d47a990bd7b048a4b2d213daaa5fb8ed670fb85f13bdbcf)
@@ -465,7 +476,7 @@ BOOST_AUTO_TEST_CASE(knapsack_solver_test)
for (int j = 0; j < 20; j++)
add_coin(50000 * COIN);
- BOOST_CHECK( testWallet.AttemptSelection(500000 * COIN, filter_confirmed, vCoins, setCoinsRet, nValueRet, coin_selection_params));
+ BOOST_CHECK(KnapsackSolver(500000 * COIN, KnapsackGroupOutputs(filter_confirmed), setCoinsRet, nValueRet));
BOOST_CHECK_EQUAL(nValueRet, 500000 * COIN); // we should get the exact amount
BOOST_CHECK_EQUAL(setCoinsRet.size(), 10U); // in ten coins
@@ -478,7 +489,7 @@ BOOST_AUTO_TEST_CASE(knapsack_solver_test)
add_coin(MIN_CHANGE * 6 / 10);
add_coin(MIN_CHANGE * 7 / 10);
add_coin(1111 * MIN_CHANGE);
- BOOST_CHECK( testWallet.AttemptSelection(1 * MIN_CHANGE, filter_confirmed, vCoins, setCoinsRet, nValueRet, coin_selection_params));
+ BOOST_CHECK(KnapsackSolver(1 * MIN_CHANGE, KnapsackGroupOutputs(filter_confirmed), setCoinsRet, nValueRet));
BOOST_CHECK_EQUAL(nValueRet, 1111 * MIN_CHANGE); // we get the bigger coin
BOOST_CHECK_EQUAL(setCoinsRet.size(), 1U);
@@ -488,7 +499,7 @@ BOOST_AUTO_TEST_CASE(knapsack_solver_test)
add_coin(MIN_CHANGE * 6 / 10);
add_coin(MIN_CHANGE * 8 / 10);
add_coin(1111 * MIN_CHANGE);
- BOOST_CHECK( testWallet.AttemptSelection(MIN_CHANGE, filter_confirmed, vCoins, setCoinsRet, nValueRet, coin_selection_params));
+ BOOST_CHECK(KnapsackSolver(MIN_CHANGE, KnapsackGroupOutputs(filter_confirmed), setCoinsRet, nValueRet));
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
@@ -499,12 +510,12 @@ BOOST_AUTO_TEST_CASE(knapsack_solver_test)
add_coin(MIN_CHANGE * 100);
// trying to make 100.01 from these three coins
- BOOST_CHECK(testWallet.AttemptSelection(MIN_CHANGE * 10001 / 100, filter_confirmed, vCoins, setCoinsRet, nValueRet, coin_selection_params));
+ BOOST_CHECK(KnapsackSolver(MIN_CHANGE * 10001 / 100, KnapsackGroupOutputs(filter_confirmed), setCoinsRet, nValueRet));
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.AttemptSelection(MIN_CHANGE * 9990 / 100, filter_confirmed, vCoins, setCoinsRet, nValueRet, coin_selection_params));
+ BOOST_CHECK(KnapsackSolver(MIN_CHANGE * 9990 / 100, KnapsackGroupOutputs(filter_confirmed), setCoinsRet, nValueRet));
BOOST_CHECK_EQUAL(nValueRet, 101 * MIN_CHANGE);
BOOST_CHECK_EQUAL(setCoinsRet.size(), 2U);
}
@@ -518,7 +529,7 @@ BOOST_AUTO_TEST_CASE(knapsack_solver_test)
// We only create the wallet once to save time, but we still run the coin selection RUN_TESTS times.
for (int i = 0; i < RUN_TESTS; i++) {
- BOOST_CHECK(testWallet.AttemptSelection(2000, filter_confirmed, vCoins, setCoinsRet, nValueRet, coin_selection_params));
+ BOOST_CHECK(KnapsackSolver(2000, KnapsackGroupOutputs(filter_confirmed), setCoinsRet, nValueRet));
if (amt - 2000 < MIN_CHANGE) {
// needs more than one input:
@@ -603,7 +614,7 @@ BOOST_AUTO_TEST_CASE(ApproximateBestSubset)
add_coin(1000 * COIN);
add_coin(3 * COIN);
- BOOST_CHECK(testWallet.AttemptSelection(1003 * COIN, filter_standard, vCoins, setCoinsRet, nValueRet, coin_selection_params));
+ BOOST_CHECK(KnapsackSolver(1003 * COIN, KnapsackGroupOutputs(filter_standard), setCoinsRet, nValueRet));
BOOST_CHECK_EQUAL(nValueRet, 1003 * COIN);
BOOST_CHECK_EQUAL(setCoinsRet.size(), 2U);
@@ -651,4 +662,73 @@ BOOST_AUTO_TEST_CASE(SelectCoins_test)
}
}
+BOOST_AUTO_TEST_CASE(waste_test)
+{
+ CoinSet selection;
+ const CAmount fee{100};
+ const CAmount change_cost{125};
+ const CAmount fee_diff{40};
+ const CAmount in_amt{3 * COIN};
+ const CAmount target{2 * COIN};
+ const CAmount excess{in_amt - fee * 2 - target};
+
+ // Waste with change is the change cost and difference between fee and long term fee
+ add_coin(1 * COIN, 1, selection, fee, fee - fee_diff);
+ add_coin(2 * COIN, 2, selection, fee, fee - fee_diff);
+ const CAmount waste1 = GetSelectionWaste(selection, change_cost, target);
+ BOOST_CHECK_EQUAL(fee_diff * 2 + change_cost, waste1);
+ selection.clear();
+
+ // Waste without change is the excess and difference between fee and long term fee
+ add_coin(1 * COIN, 1, selection, fee, fee - fee_diff);
+ add_coin(2 * COIN, 2, selection, fee, fee - fee_diff);
+ const CAmount waste_nochange1 = GetSelectionWaste(selection, 0, target);
+ BOOST_CHECK_EQUAL(fee_diff * 2 + excess, waste_nochange1);
+ selection.clear();
+
+ // Waste with change and fee == long term fee is just cost of change
+ add_coin(1 * COIN, 1, selection, fee, fee);
+ add_coin(2 * COIN, 2, selection, fee, fee);
+ BOOST_CHECK_EQUAL(change_cost, GetSelectionWaste(selection, change_cost, target));
+ selection.clear();
+
+ // Waste without change and fee == long term fee is just the excess
+ add_coin(1 * COIN, 1, selection, fee, fee);
+ add_coin(2 * COIN, 2, selection, fee, fee);
+ BOOST_CHECK_EQUAL(excess, GetSelectionWaste(selection, 0, target));
+ selection.clear();
+
+ // Waste will be greater when fee is greater, but long term fee is the same
+ add_coin(1 * COIN, 1, selection, fee * 2, fee - fee_diff);
+ add_coin(2 * COIN, 2, selection, fee * 2, fee - fee_diff);
+ const CAmount waste2 = GetSelectionWaste(selection, change_cost, target);
+ BOOST_CHECK_GT(waste2, waste1);
+ selection.clear();
+
+ // Waste with change is the change cost and difference between fee and long term fee
+ // With long term fee greater than fee, waste should be less than when long term fee is less than fee
+ add_coin(1 * COIN, 1, selection, fee, fee + fee_diff);
+ add_coin(2 * COIN, 2, selection, fee, fee + fee_diff);
+ const CAmount waste3 = GetSelectionWaste(selection, change_cost, target);
+ BOOST_CHECK_EQUAL(fee_diff * -2 + change_cost, waste3);
+ BOOST_CHECK_LT(waste3, waste1);
+ selection.clear();
+
+ // Waste without change is the excess and difference between fee and long term fee
+ // With long term fee greater than fee, waste should be less than when long term fee is less than fee
+ add_coin(1 * COIN, 1, selection, fee, fee + fee_diff);
+ add_coin(2 * COIN, 2, selection, fee, fee + fee_diff);
+ const CAmount waste_nochange2 = GetSelectionWaste(selection, 0, target);
+ BOOST_CHECK_EQUAL(fee_diff * -2 + excess, waste_nochange2);
+ BOOST_CHECK_LT(waste_nochange2, waste_nochange1);
+ selection.clear();
+
+ // 0 Waste only when fee == long term fee, no change, and no excess
+ add_coin(1 * COIN, 1, selection, fee, fee);
+ add_coin(2 * COIN, 2, selection, fee, fee);
+ const CAmount exact_target = in_amt - 2 * fee;
+ BOOST_CHECK_EQUAL(0, GetSelectionWaste(selection, 0, exact_target));
+
+}
+
BOOST_AUTO_TEST_SUITE_END()