1 files changed, 45 insertions, 0 deletions
diff --git a/src/wallet/test/spend_tests.cpp b/src/wallet/test/spend_tests.cpp
index a75b014870..81a8883f85 100644
--- a/src/wallet/test/spend_tests.cpp
+++ b/src/wallet/test/spend_tests.cpp
@@ -112,5 +112,50 @@ BOOST_FIXTURE_TEST_CASE(FillInputToWeightTest, BasicTestingSetup)
     // Note: We don't test the next boundary because of memory allocation constraints.
 }
 
+BOOST_FIXTURE_TEST_CASE(wallet_duplicated_preset_inputs_test, TestChain100Setup)
+{
+    // Verify that the wallet's Coin Selection process does not include pre-selected inputs twice in a transaction.
+
+    // Add 4 spendable UTXO, 50 BTC each, to the wallet (total balance 200 BTC)
+    for (int i = 0; i < 4; i++) CreateAndProcessBlock({}, GetScriptForRawPubKey(coinbaseKey.GetPubKey()));
+    auto wallet = CreateSyncedWallet(*m_node.chain, WITH_LOCK(Assert(m_node.chainman)->GetMutex(), return m_node.chainman->ActiveChain()), m_args, coinbaseKey);
+
+    LOCK(wallet->cs_wallet);
+    auto available_coins = AvailableCoins(*wallet);
+    std::vector<COutput> coins = available_coins.All();
+    // Preselect the first 3 UTXO (150 BTC total)
+    std::set<COutPoint> preset_inputs = {coins[0].outpoint, coins[1].outpoint, coins[2].outpoint};
+
+    // Try to create a tx that spends more than what preset inputs + wallet selected inputs are covering for.
+    // The wallet can cover up to 200 BTC, and the tx target is 299 BTC.
+    std::vector<CRecipient> recipients = {{GetScriptForDestination(*Assert(wallet->GetNewDestination(OutputType::BECH32, "dummy"))),
+                                           /*nAmount=*/299 * COIN, /*fSubtractFeeFromAmount=*/true}};
+    CCoinControl coin_control;
+    coin_control.m_allow_other_inputs = true;
+    for (const auto& outpoint : preset_inputs) {
+        coin_control.Select(outpoint);
+    }
+
+    // Attempt to send 299 BTC from a wallet that only has 200 BTC. The wallet should exclude
+    // the preset inputs from the pool of available coins, realize that there is not enough
+    // money to fund the 299 BTC payment, and fail with "Insufficient funds".
+    //
+    // Even with SFFO, the wallet can only afford to send 200 BTC.
+    // If the wallet does not properly exclude preset inputs from the pool of available coins
+    // prior to coin selection, it may create a transaction that does not fund the full payment
+    // amount or, through SFFO, incorrectly reduce the recipient's amount by the difference
+    // between the original target and the wrongly counted inputs (in this case 99 BTC)
+    // so that the recipient's amount is no longer equal to the user's selected target of 299 BTC.
+
+    // First case, use 'subtract_fee_from_outputs=true'
+    util::Result<CreatedTransactionResult> res_tx = CreateTransaction(*wallet, recipients, /*change_pos*/-1, coin_control);
+    BOOST_CHECK(!res_tx.has_value());
+
+    // Second case, don't use 'subtract_fee_from_outputs'.
+    recipients[0].fSubtractFeeFromAmount = false;
+    res_tx = CreateTransaction(*wallet, recipients, /*change_pos*/-1, coin_control);
+    BOOST_CHECK(!res_tx.has_value());
+}
+
 BOOST_AUTO_TEST_SUITE_END()
 } // namespace wallet