Move SelectCoins max_weight test

src/Makefile.test.include

@@ -181,7 +181,6 @@ BITCOIN_TESTS += \
   wallet/test/walletdb_tests.cpp \
   wallet/test/wallet_crypto_tests.cpp \
   wallet/test/wallet_transaction_tests.cpp \
-  wallet/test/coinselector_tests.cpp \
   wallet/test/coinselection_tests.cpp \
   wallet/test/init_tests.cpp \
   wallet/test/ismine_tests.cpp \

src/wallet/test/coinselection_tests.cpp

@@ -779,6 +779,121 @@ BOOST_AUTO_TEST_CASE(bump_fee_test)
 ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 /////////////////////////////////////////  SelectCoins Test  ///////////////////////////////////////////////////////////
 ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+static bool HasCoin(const CoinSet& set, CAmount amount)
+{
+    return std::any_of(set.begin(), set.end(), [&](const auto& coin) { return coin->GetEffectiveValue() == amount; });
+}
+
+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)
+{
+    std::unique_ptr<CWallet> wallet = NewWallet(m_node);
+    auto available_coins = coin_setup(*wallet);
+
+    LOCK(wallet->cs_wallet);
+    auto result = SelectCoins(*wallet, available_coins, /*pre_set_inputs=*/ {}, target, cc, cs_params);
+    if (result) {
+        const auto signedTxSize = 10 + 34 + 68 * result->GetInputSet().size(); // static header size + output size + inputs size (P2WPKH)
+        BOOST_CHECK_LE(signedTxSize * WITNESS_SCALE_FACTOR, MAX_STANDARD_TX_WEIGHT);
+
+        BOOST_CHECK_GE(result->GetSelectedValue(), target);
+    }
+    return result;
+}
+
+BOOST_AUTO_TEST_CASE(check_max_weight)
+{
+    const CAmount target = 49.5L * COIN;
+    CCoinControl cc;
+
+    FastRandomContext rand;
+    CoinSelectionParams cs_params{
+        rand,
+        /*change_output_size=*/34,
+        /*change_spend_size=*/68,
+        /*min_change_target=*/CENT,
+        /*effective_feerate=*/CFeeRate(0),
+        /*long_term_feerate=*/CFeeRate(0),
+        /*discard_feerate=*/CFeeRate(0),
+        /*tx_noinputs_size=*/10 + 34, // static header size + output size
+        /*avoid_partial=*/false,
+    };
+
+    {
+        // Scenario 1:
+        // The actor starts with 1x 50.0 BTC and 1515x 0.033 BTC (~100.0 BTC total) unspent outputs
+        // Then tries to spend 49.5 BTC
+        // The 50.0 BTC output should be selected, because the transaction would otherwise be too large
+
+        // Perform selection
+
+        const auto result = select_coins(
+            target, cs_params, cc, [&](CWallet& wallet) {
+                CoinsResult available_coins;
+                for (int j = 0; j < 1515; ++j) {
+                    AddCoinToWallet(available_coins, wallet, CAmount(0.033 * COIN), CFeeRate(0), 144, false, 0, true);
+                }
+
+                AddCoinToWallet(available_coins, wallet, CAmount(50 * COIN), CFeeRate(0), 144, false, 0, true);
+                return available_coins;
+            },
+            m_node);
+
+        BOOST_CHECK(result);
+        // Verify that only the 50 BTC UTXO was selected
+        const auto& selection_res = result->GetInputSet();
+        BOOST_CHECK(selection_res.size() == 1);
+        BOOST_CHECK((*selection_res.begin())->GetEffectiveValue() == 50 * COIN);
+    }
+
+    {
+        // Scenario 2:
+
+        // The actor starts with 400x 0.0625 BTC and 2000x 0.025 BTC (75.0 BTC total) unspent outputs
+        // Then tries to spend 49.5 BTC
+        // A combination of coins should be selected, such that the created transaction is not too large
+
+        // Perform selection
+        const auto result = select_coins(
+            target, cs_params, cc, [&](CWallet& wallet) {
+                CoinsResult available_coins;
+                for (int j = 0; j < 400; ++j) {
+                    AddCoinToWallet(available_coins, wallet, CAmount(0.0625 * COIN), CFeeRate(0), 144, false, 0, true);
+                }
+                for (int j = 0; j < 2000; ++j) {
+                    AddCoinToWallet(available_coins, wallet, CAmount(0.025 * COIN), CFeeRate(0), 144, false, 0, true);
+                }
+                return available_coins;
+            },
+            m_node);
+
+        BOOST_CHECK(HasCoin(result->GetInputSet(), CAmount(0.0625 * COIN)));
+        BOOST_CHECK(HasCoin(result->GetInputSet(), CAmount(0.025 * COIN)));
+    }
+
+    {
+        // Scenario 3:
+
+        // The actor starts with 1515x 0.033 BTC (49.995 BTC total) unspent outputs
+        // No results should be returned, because the transaction would be too large
+
+        // Perform selection
+        const auto result = select_coins(
+            target, cs_params, cc, [&](CWallet& wallet) {
+                CoinsResult available_coins;
+                for (int j = 0; j < 1515; ++j) {
+                    AddCoinToWallet(available_coins, wallet, CAmount(0.033 * COIN), CFeeRate(0), 144, false, 0, true);
+                }
+                return available_coins;
+            },
+            m_node);
+
+        // No results
+        // 1515 inputs * 68 bytes = 103,020 bytes
+        // 103,020 bytes * 4 = 412,080 weight, which is above the MAX_STANDARD_TX_WEIGHT of 400,000
+        BOOST_CHECK(!result);
+    }
+}
+
 // 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)
 {