core: Implement sendBsqTest

First, the sendBsq test creates one BTC and two BSQ wallets. Afterward,
it funds the BTC and one BSQ wallet with 1 BTC. Next, the funded BSQ
wallet sends 100 BSQ to the second BSQ wallet.

core/build.gradle

@@ -68,6 +68,14 @@ dependencies {
     integrationTestImplementation('bitcoind:regtest') {
         exclude(module: 'kotlin-stdlib-jdk8')
     }
+    integrationTestImplementation libs.hamcrest
+    integrationTestImplementation libs.mockito.core
+    integrationTestImplementation libs.mockito.junit.jupiter
+
+    integrationTestImplementation libs.junit.jupiter.api
+    integrationTestImplementation libs.junit.jupiter.params
+
+    integrationTestRuntimeOnly libs.junit.jupiter.engine
 }
 
 test {

core/src/integrationTest/java/bisq/core/BitcoinjBsqTests.java

@@ -0,0 +1,148 @@
+package bisq.core;
+
+import bisq.core.btc.exceptions.BsqChangeBelowDustException;
+import bisq.core.btc.wallet.BisqDefaultCoinSelector;
+import bisq.core.btc.wallet.BsqCoinSelector;
+import bisq.core.btc.wallet.BsqWalletV2;
+import bisq.core.btc.wallet.BtcWalletV2;
+import bisq.core.btc.wallet.WalletFactory;
+import bisq.core.dao.state.DaoStateService;
+import bisq.core.dao.state.model.blockchain.TxOutputKey;
+import bisq.core.dao.state.unconfirmed.UnconfirmedBsqChangeOutputListService;
+
+import org.bitcoinj.core.Address;
+import org.bitcoinj.core.Coin;
+import org.bitcoinj.core.InsufficientMoneyException;
+import org.bitcoinj.core.TransactionOutput;
+import org.bitcoinj.kits.WalletAppKit;
+import org.bitcoinj.params.RegTestParams;
+import org.bitcoinj.wallet.Wallet;
+
+import java.nio.file.Path;
+
+import java.util.List;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+
+import lombok.extern.slf4j.Slf4j;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.junit.jupiter.api.io.TempDir;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.doReturn;
+import static org.mockito.Mockito.mock;
+
+
+
+import bisq.wallets.regtest.BitcoindExtension;
+import bisq.wallets.regtest.bitcoind.BitcoindRegtestSetup;
+
+@ExtendWith(BitcoindExtension.class)
+@Slf4j
+public class BitcoinjBsqTests {
+
+    private static class BisqRegtestNetworkParams extends RegTestParams {
+        public void setPort(int port) {
+            this.port = port;
+        }
+    }
+
+    private final BitcoindRegtestSetup regtestSetup;
+    private final BisqRegtestNetworkParams networkParams;
+
+    public BitcoinjBsqTests(BitcoindRegtestSetup regtestSetup) {
+        this.regtestSetup = regtestSetup;
+        networkParams = new BisqRegtestNetworkParams();
+        networkParams.setPort(regtestSetup.getP2pPort());
+    }
+
+    @Test
+    void sendBsqTest(@TempDir Path tempDir) throws InterruptedException, InsufficientMoneyException, BsqChangeBelowDustException {
+        var walletFactory = new WalletFactory(networkParams);
+        Wallet btcWallet = walletFactory.createBtcWallet();
+        Wallet secondBsqWallet = walletFactory.createBsqWallet();
+
+        var wallets = List.of(btcWallet, secondBsqWallet);
+        var regtestWalletAppKit = new RegtestWalletAppKit(networkParams, tempDir, wallets);
+        regtestWalletAppKit.initialize();
+
+        WalletAppKit walletAppKit = regtestWalletAppKit.getWalletAppKit();
+        Wallet bsqWallet = walletAppKit.wallet();
+
+        var bsqWalletReceivedLatch = new CountDownLatch(1);
+        bsqWallet.addCoinsReceivedEventListener((wallet, tx, prevBalance, newBalance) ->
+                bsqWalletReceivedLatch.countDown());
+
+        var btcWalletReceivedLatch = new CountDownLatch(1);
+        btcWallet.addCoinsReceivedEventListener((wallet, tx, prevBalance, newBalance) ->
+                btcWalletReceivedLatch.countDown());
+
+        Address currentReceiveAddress = bsqWallet.currentReceiveAddress();
+        String address = currentReceiveAddress.toString();
+        regtestSetup.fundAddress(address, 1.0);
+
+        currentReceiveAddress = btcWallet.currentReceiveAddress();
+        address = currentReceiveAddress.toString();
+        regtestSetup.fundAddress(address, 1.0);
+
+        regtestSetup.mineOneBlock();
+
+        boolean isSuccess = bsqWalletReceivedLatch.await(30, TimeUnit.SECONDS);
+        assertThat("BSQ wallet not funded after 30 seconds.", isSuccess);
+
+        Coin balance = bsqWallet.getBalance();
+        assertThat("BitcoinJ BSQ wallet balance should equal 1 BTC.", balance.equals(Coin.COIN));
+
+        isSuccess = btcWalletReceivedLatch.await(30, TimeUnit.SECONDS);
+        assertThat("BTC wallet not funded after 30 seconds.", isSuccess);
+
+        balance = btcWallet.getBalance();
+        assertThat("BitcoinJ BTC wallet balance should equal 1 BTC.", balance.equals(Coin.COIN));
+
+        DaoStateService daoStateService = mock(DaoStateService.class);
+        doReturn(true).when(daoStateService)
+                .isTxOutputSpendable(any(TxOutputKey.class));
+
+        var bsqCoinSelector = new BsqCoinSelector(daoStateService, mock(UnconfirmedBsqChangeOutputListService.class));
+        var btcCoinSelector = new BisqDefaultCoinSelector(true) {
+            @Override
+            protected boolean isDustAttackUtxo(TransactionOutput output) {
+                return false;
+            }
+
+            @Override
+            protected boolean isTxOutputSpendable(TransactionOutput output) {
+                return true;
+            }
+        };
+
+        var btcWalletV2 = new BtcWalletV2(btcCoinSelector, btcWallet);
+        var bsqWalletV2 = new BsqWalletV2(networkParams,
+                walletAppKit.peerGroup(),
+                btcWalletV2,
+                bsqWallet,
+                bsqCoinSelector);
+
+        var secondBsqWalletReceivedLatch = new CountDownLatch(1);
+        secondBsqWallet.addCoinsReceivedEventListener((wallet, tx, prevBalance, newBalance) ->
+                secondBsqWalletReceivedLatch.countDown());
+
+        // Send 100 BSQ (1 BSQ = 100 Satoshis)
+        Address receiverAddress = secondBsqWallet.currentReceiveAddress();
+        Coin receiverAmount = Coin.ofSat(100 * 100);
+        bsqWalletV2.sendBsq(receiverAddress, receiverAmount, Coin.ofSat(10));
+
+        regtestSetup.mineOneBlock();
+
+        isSuccess = secondBsqWalletReceivedLatch.await(30, TimeUnit.SECONDS);
+        assertThat("Didn't receive BSQ after 30 seconds.", isSuccess);
+
+        assertEquals(bsqWallet.getBalance(), Coin.ofSat(99990000));
+        assertEquals(btcWallet.getBalance(), Coin.ofSat(99999747));
+        assertEquals(secondBsqWallet.getBalance(), Coin.ofSat(10000));
+    }
+}

core/src/main/java/bisq/core/btc/wallet/BisqDefaultCoinSelector.java

@@ -134,7 +134,7 @@ protected boolean isTxSpendable(Transaction tx) {
         return isConfirmed || (isPending && (permitForeignPendingTx || isOwnTx));
     }
 
-    abstract boolean isTxOutputSpendable(TransactionOutput output);
+    protected abstract boolean isTxOutputSpendable(TransactionOutput output);
 
     // TODO Why it uses coin age and not try to minimize number of inputs as the highest priority?
     //      Asked Oscar and he also don't knows why coin age is used. Should be changed so that min. number of inputs is

core/src/main/java/bisq/core/btc/wallet/BtcCoinSelector.java

@@ -31,7 +31,7 @@
  * We lookup for spendable outputs which matches any of our addresses.
  */
 @Slf4j
-class BtcCoinSelector extends BisqDefaultCoinSelector {
+public class BtcCoinSelector extends BisqDefaultCoinSelector {
     private final Set<Address> addresses;
     private final long ignoreDustThreshold;