test: coverage for bnb max weight

Basic positive and negative scenarios

Author: furszy

src/wallet/test/coinselector_tests.cpp

@@ -68,7 +68,7 @@ static void add_coin(const CAmount& nValue, int nInput, CoinSet& set, CAmount fe
     set.insert(std::make_shared<COutput>(coin));
 }
 
-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)
+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)
 {
     CMutableTransaction tx;
     tx.nLockTime = nextLockTime++;        // so all transactions get different hashes
@@ -84,7 +84,7 @@ static void add_coin(CoinsResult& available_coins, CWallet& wallet, const CAmoun
     assert(ret.second);
     CWalletTx& wtx = (*ret.first).second;
     const auto& txout = wtx.tx->vout.at(nInput);
-    available_coins.Add(OutputType::BECH32, {COutPoint(wtx.GetHash(), nInput), txout, nAge, CalculateMaximumSignedInputSize(txout, &wallet, /*coin_control=*/nullptr), /*spendable=*/ true, /*solvable=*/ true, /*safe=*/ true, wtx.GetTxTime(), fIsFromMe, feerate});
+    available_coins.Add(OutputType::BECH32, {COutPoint(wtx.GetHash(), nInput), txout, nAge, custom_size == 0 ? CalculateMaximumSignedInputSize(txout, &wallet, /*coin_control=*/nullptr) : custom_size, /*spendable=*/ true, /*solvable=*/ true, /*safe=*/ true, wtx.GetTxTime(), fIsFromMe, feerate});
 }
 
 // Helpers
@@ -142,13 +142,15 @@ static CAmount make_hard_case(int utxos, std::vector<COutput>& utxo_pool)
     return target;
 }
 
-inline std::vector<OutputGroup>& GroupCoins(const std::vector<COutput>& available_coins)
+inline std::vector<OutputGroup>& GroupCoins(const std::vector<COutput>& available_coins, bool subtract_fee_outputs = false)
 {
     static std::vector<OutputGroup> static_groups;
     static_groups.clear();
     for (auto& coin : available_coins) {
         static_groups.emplace_back();
-        static_groups.back().Insert(std::make_shared<COutput>(coin), /*ancestors=*/ 0, /*descendants=*/ 0);
+        OutputGroup& group = static_groups.back();
+        group.Insert(std::make_shared<COutput>(coin), /*ancestors=*/ 0, /*descendants=*/ 0);
+        group.m_subtract_fee_outputs = subtract_fee_outputs;
     }
     return static_groups;
 }
@@ -411,6 +413,41 @@ BOOST_AUTO_TEST_CASE(bnb_search_test)
         const auto result13 = SelectCoins(*wallet, available_coins, selected_input, 10 * CENT, coin_control, coin_selection_params_bnb);
         BOOST_CHECK(EquivalentResult(expected_result, *result13));
     }
+
+    {
+        // Test bnb max weight exceeded
+        // Inputs set [10, 9, 8, 5, 3, 1], Selection Target = 16 and coin 5 exceeding the max weight.
+
+        std::unique_ptr<CWallet> wallet = std::make_unique<CWallet>(m_node.chain.get(), "", m_args, CreateMockWalletDatabase());
+        wallet->LoadWallet();
+        LOCK(wallet->cs_wallet);
+        wallet->SetWalletFlag(WALLET_FLAG_DESCRIPTORS);
+        wallet->SetupDescriptorScriptPubKeyMans();
+
+        CoinsResult available_coins;
+        add_coin(available_coins, *wallet, 10 * CENT, coin_selection_params_bnb.m_effective_feerate, 6 * 24, false, 0, true);
+        add_coin(available_coins, *wallet, 9 * CENT, coin_selection_params_bnb.m_effective_feerate, 6 * 24, false, 0, true);
+        add_coin(available_coins, *wallet, 8 * CENT, coin_selection_params_bnb.m_effective_feerate, 6 * 24, false, 0, true);
+        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);
+        add_coin(available_coins, *wallet, 3 * CENT, coin_selection_params_bnb.m_effective_feerate, 6 * 24, false, 0, true);
+        add_coin(available_coins, *wallet, 1 * CENT, coin_selection_params_bnb.m_effective_feerate, 6 * 24, false, 0, true);
+
+        CAmount selection_target = 16 * CENT;
+        const auto& no_res = SelectCoinsBnB(GroupCoins(available_coins.All(), /*subtract_fee_outputs*/true),
+                                            selection_target, /*cost_of_change=*/0, MAX_STANDARD_TX_WEIGHT);
+        BOOST_ASSERT(!no_res);
+        BOOST_CHECK(util::ErrorString(no_res).original.find("The inputs size exceeds the maximum weight") != std::string::npos);
+
+        // Now add same coin value with a good size and check that it gets selected
+        add_coin(available_coins, *wallet, 5 * CENT, coin_selection_params_bnb.m_effective_feerate, 6 * 24, false, 0, true);
+        const auto& res = SelectCoinsBnB(GroupCoins(available_coins.All(), /*subtract_fee_outputs*/true), selection_target, /*cost_of_change=*/0);
+
+        expected_result.Clear();
+        add_coin(8 * CENT, 2, expected_result);
+        add_coin(5 * CENT, 2, expected_result);
+        add_coin(3 * CENT, 2, expected_result);
+        BOOST_CHECK(EquivalentResult(expected_result, *res));
+    }
 }
 
 BOOST_AUTO_TEST_CASE(knapsack_solver_test)