mod+chanfunding: use coin selection strategy for channel funding

The wallet assembler is now aware of the node config level coin
selection strategy, so we can use it when creating new channels.

itest/lnd_channel_funding_utxo_selection_test.go

@@ -11,6 +11,7 @@ import (
 	"github.com/lightningnetwork/lnd/lntest"
 	"github.com/lightningnetwork/lnd/lntest/node"
 	"github.com/lightningnetwork/lnd/lnwallet"
+	"github.com/stretchr/testify/require"
 )
 
 type chanFundUtxoSelectionTestCase struct {
@@ -131,8 +132,7 @@ func testChannelUtxoSelection(ht *lntest.HarnessTest) {
 			localAmt:        btcutil.Amount(250_000),
 			expectedBalance: btcutil.Amount(250_000),
 			remainingWalletBalance: btcutil.Amount(350_000) -
-				btcutil.Amount(250_000) -
-				fundingFee(2, true),
+				btcutil.Amount(250_000) - fundingFee(2, true),
 		},
 		// We are spending the entirety of two selected coins out of
 		// three available in the wallet and expect no change output and
@@ -147,8 +147,7 @@ func testChannelUtxoSelection(ht *lntest.HarnessTest) {
 				200_000, 50_000,
 			},
 			expectedBalance: btcutil.Amount(200_000) +
-				btcutil.Amount(50_000) -
-				fundingFee(2, false),
+				btcutil.Amount(50_000) - fundingFee(2, false),
 			remainingWalletBalance: btcutil.Amount(100_000),
 		},
 		// Select all coins in wallet and use the maximum available
@@ -162,15 +161,14 @@ func testChannelUtxoSelection(ht *lntest.HarnessTest) {
 			selectedCoins:  []btcutil.Amount{200_000, 100_000},
 			commitmentType: lnrpc.CommitmentType_ANCHORS,
 			localAmt: btcutil.Amount(300_000) -
-				reserveAmount -
-				fundingFee(2, true),
+				reserveAmount - fundingFee(2, true),
 			expectedBalance: btcutil.Amount(300_000) -
-				reserveAmount -
-				fundingFee(2, true),
+				reserveAmount - fundingFee(2, true),
 			remainingWalletBalance: reserveAmount,
 		},
-		// Select all coins in wallet towards local amount except for a
-		// anchor reserve portion.
+		// Select all coins in wallet towards local amount except for an
+		// anchor reserve portion. Because the UTXOs are sorted by size
+		// by default, the reserve amount is just left in the wallet.
 		{
 			name: "selected, reserve from selected",
 			initialCoins: []btcutil.Amount{
@@ -181,9 +179,9 @@ func testChannelUtxoSelection(ht *lntest.HarnessTest) {
 			},
 			commitmentType: lnrpc.CommitmentType_ANCHORS,
 			localAmt: btcutil.Amount(300_000) -
-				fundingFee(3, true),
+				fundingFee(2, true),
 			expectedBalance: btcutil.Amount(300_000) -
-				fundingFee(3, true),
+				fundingFee(2, true),
 			remainingWalletBalance: reserveAmount,
 		},
 		// Select all coins in wallet and use more than the maximum
@@ -197,8 +195,7 @@ func testChannelUtxoSelection(ht *lntest.HarnessTest) {
 			selectedCoins:  []btcutil.Amount{200_000, 100_000},
 			commitmentType: lnrpc.CommitmentType_ANCHORS,
 			localAmt: btcutil.Amount(300_000) -
-				reserveAmount + 1 -
-				fundingFee(2, true),
+				reserveAmount + 1 - fundingFee(2, true),
 			chanOpenShouldFail: true,
 			expectedErrStr: "reserved wallet balance " +
 				"invalidated: transaction would leave " +
@@ -229,8 +226,7 @@ func testChannelUtxoSelection(ht *lntest.HarnessTest) {
 			selectedCoins:  []btcutil.Amount{200_000},
 			commitmentType: lnrpc.CommitmentType_ANCHORS,
 			expectedBalance: btcutil.Amount(200_000) -
-				reserveAmount -
-				fundingFee(1, true),
+				reserveAmount - fundingFee(1, true),
 			remainingWalletBalance: reserveAmount,
 		},
 		// Confirm that already spent outputs can't be reused to fund
@@ -249,8 +245,7 @@ func testChannelUtxoSelection(ht *lntest.HarnessTest) {
 		success := ht.Run(
 			tc.name, func(tt *testing.T) {
 				runUtxoSelectionTestCase(
-					ht, tt, alice, bob, tc,
-					reserveAmount,
+					ht, alice, bob, tc, reserveAmount,
 				)
 			},
 		)
@@ -264,7 +259,7 @@ func testChannelUtxoSelection(ht *lntest.HarnessTest) {
 
 // runUtxoSelectionTestCase runs a single test case asserting that test
 // conditions are met.
-func runUtxoSelectionTestCase(ht *lntest.HarnessTest, t *testing.T, alice,
+func runUtxoSelectionTestCase(ht *lntest.HarnessTest, alice,
 	bob *node.HarnessNode, tc *chanFundUtxoSelectionTestCase,
 	reserveAmount btcutil.Amount) {
 
@@ -366,4 +361,12 @@ func runUtxoSelectionTestCase(ht *lntest.HarnessTest, t *testing.T, alice,
 		int64(tc.remainingWalletBalance),
 		0,
 	)
+
+	// Ensure the anchor channel reserve was carved out.
+	if commitType == lnrpc.CommitmentType_ANCHORS {
+		balance := alice.RPC.WalletBalance()
+		require.EqualValues(
+			ht, reserveAmount, balance.ReservedBalanceAnchorChan,
+		)
+	}
 }