itest: test imported address in coop close

Make sure that an address imported to LND via ImportTapscript or ImportPublicKey
can be used as a delivery address in coop close.

New test cases:
 - P2TR address imported with ImportTapscript
 - P2TR address imported with ImportPublicKey
 - P2WPKH address imported with ImportPublicKey

Safeguard against https://github.com/lightninglabs/loop/issues/923

itest/lnd_coop_close_external_delivery_test.go

@@ -4,7 +4,9 @@ import (
 	"fmt"
 
 	"github.com/btcsuite/btcd/btcutil"
+	"github.com/btcsuite/btcd/txscript"
 	"github.com/lightningnetwork/lnd/lnrpc"
+	"github.com/lightningnetwork/lnd/lnrpc/walletrpc"
 	"github.com/lightningnetwork/lnd/lntest"
 	"github.com/lightningnetwork/lnd/lntest/wait"
 	"github.com/stretchr/testify/require"
@@ -15,7 +17,7 @@ var coopCloseWithExternalTestCases = []*lntest.TestCase{
 		Name: "set P2WPKH delivery address at open",
 		TestFunc: func(ht *lntest.HarnessTest) {
 			testCoopCloseWithExternalDelivery(
-				ht, true,
+				ht, true, false, false,
 				lnrpc.AddressType_UNUSED_WITNESS_PUBKEY_HASH,
 			)
 		},
@@ -24,7 +26,7 @@ var coopCloseWithExternalTestCases = []*lntest.TestCase{
 		Name: "set P2WPKH delivery address at close",
 		TestFunc: func(ht *lntest.HarnessTest) {
 			testCoopCloseWithExternalDelivery(
-				ht, false,
+				ht, false, false, false,
 				lnrpc.AddressType_UNUSED_WITNESS_PUBKEY_HASH,
 			)
 		},
@@ -33,7 +35,7 @@ var coopCloseWithExternalTestCases = []*lntest.TestCase{
 		Name: "set P2TR delivery address at open",
 		TestFunc: func(ht *lntest.HarnessTest) {
 			testCoopCloseWithExternalDelivery(
-				ht, true,
+				ht, true, false, false,
 				lnrpc.AddressType_UNUSED_TAPROOT_PUBKEY,
 			)
 		},
@@ -42,7 +44,61 @@ var coopCloseWithExternalTestCases = []*lntest.TestCase{
 		Name: "set P2TR delivery address at close",
 		TestFunc: func(ht *lntest.HarnessTest) {
 			testCoopCloseWithExternalDelivery(
-				ht, false,
+				ht, false, false, false,
+				lnrpc.AddressType_UNUSED_TAPROOT_PUBKEY,
+			)
+		},
+	},
+	{
+		Name: "set imported P2TR address (ImportTapscript) at open",
+		TestFunc: func(ht *lntest.HarnessTest) {
+			testCoopCloseWithExternalDelivery(
+				ht, true, true, false,
+				lnrpc.AddressType_UNUSED_TAPROOT_PUBKEY,
+			)
+		},
+	},
+	{
+		Name: "set imported P2TR address (ImportTapscript) at close",
+		TestFunc: func(ht *lntest.HarnessTest) {
+			testCoopCloseWithExternalDelivery(
+				ht, false, true, false,
+				lnrpc.AddressType_UNUSED_TAPROOT_PUBKEY,
+			)
+		},
+	},
+	{
+		Name: "set imported P2WPKH address at open",
+		TestFunc: func(ht *lntest.HarnessTest) {
+			testCoopCloseWithExternalDelivery(
+				ht, true, false, true,
+				lnrpc.AddressType_UNUSED_WITNESS_PUBKEY_HASH,
+			)
+		},
+	},
+	{
+		Name: "set imported P2WPKH address at close",
+		TestFunc: func(ht *lntest.HarnessTest) {
+			testCoopCloseWithExternalDelivery(
+				ht, false, false, true,
+				lnrpc.AddressType_UNUSED_WITNESS_PUBKEY_HASH,
+			)
+		},
+	},
+	{
+		Name: "set imported P2TR address (ImportPublicKey) at open",
+		TestFunc: func(ht *lntest.HarnessTest) {
+			testCoopCloseWithExternalDelivery(
+				ht, true, false, true,
+				lnrpc.AddressType_UNUSED_TAPROOT_PUBKEY,
+			)
+		},
+	},
+	{
+		Name: "set imported P2TR address (ImportPublicKey) at close",
+		TestFunc: func(ht *lntest.HarnessTest) {
+			testCoopCloseWithExternalDelivery(
+				ht, false, false, true,
 				lnrpc.AddressType_UNUSED_TAPROOT_PUBKEY,
 			)
 		},
@@ -53,20 +109,102 @@ var coopCloseWithExternalTestCases = []*lntest.TestCase{
 // balance irrespective of whether the delivery address is in LND's wallet or
 // not. Some users set this value to be an address in a different wallet and
 // this should not affect our ability to accurately report the settled balance.
+//
+// If importTapscript is set, it imports a Taproot script and internal key to
+// Alice's LND using ImportTapscript to make sure it doesn't interfere with
+// delivery address. If importPubkey is set, the address is imported using
+// ImportPublicKey.
 func testCoopCloseWithExternalDelivery(ht *lntest.HarnessTest,
-	upfrontShutdown bool, deliveryAddressType lnrpc.AddressType) {
+	upfrontShutdown, importTapscript, importPubkey bool,
+	deliveryAddressType lnrpc.AddressType) {
 
 	alice := ht.NewNodeWithCoins("Alice", nil)
 	bob := ht.NewNodeWithCoins("bob", nil)
 	ht.ConnectNodes(alice, bob)
 
+	// Make fake taproot internal public key (equal to the final).
+	// This is only used if importTapscript or importPubkey is set.
+	taprootPubkey := [32]byte{1, 2, 3}
+	if upfrontShutdown {
+		// Make new address for second sub-test not to import
+		// the same address twice causing an error.
+		taprootPubkey[3] = 1
+	}
+	pkScriptBytes := append(
+		[]byte{txscript.OP_1, txscript.OP_DATA_32},
+		taprootPubkey[:]...,
+	)
+	pkScript, err := txscript.ParsePkScript(pkScriptBytes)
+	require.NoError(ht, err)
+	taprootAddress, err := pkScript.Address(harnessNetParams)
+	require.NoError(ht, err)
+
+	var addr string
+	switch {
+	// Use ImportTapscript.
+	case importTapscript:
+		addr = taprootAddress.String()
+
+		// Import the taproot address to LND.
+		req := &walletrpc.ImportTapscriptRequest{
+			InternalPublicKey: taprootPubkey[:],
+			Script: &walletrpc.ImportTapscriptRequest_FullKeyOnly{
+				FullKeyOnly: true,
+			},
+		}
+		res := alice.RPC.ImportTapscript(req)
+		require.Equal(ht, addr, res.P2TrAddress)
+
+	// Use ImportPublicKey.
+	case importPubkey:
+		var (
+			address     btcutil.Address
+			pubKey      []byte
+			addressType walletrpc.AddressType
+		)
+		switch deliveryAddressType {
+		case lnrpc.AddressType_UNUSED_WITNESS_PUBKEY_HASH:
+			// Make fake public key hash.
+			pk := [33]byte{2, 3, 4}
+			if upfrontShutdown {
+				// Make new address for second sub-test.
+				pk[1]++
+			}
+			address, err = btcutil.NewAddressWitnessPubKeyHash(
+				btcutil.Hash160(pk[:]), harnessNetParams,
+			)
+			require.NoError(ht, err)
+			pubKey = pk[:]
+			addressType = walletrpc.AddressType_WITNESS_PUBKEY_HASH
+
+		case lnrpc.AddressType_UNUSED_TAPROOT_PUBKEY:
+			address = taprootAddress
+			pubKey = taprootPubkey[:]
+			addressType = walletrpc.AddressType_TAPROOT_PUBKEY
+
+		default:
+			ht.Fatalf("not allowed address type: %v",
+				deliveryAddressType)
+		}
+
+		addr = address.String()
+
+		// Import the address to LND.
+		alice.RPC.ImportPublicKey(&walletrpc.ImportPublicKeyRequest{
+			PublicKey:   pubKey,
+			AddressType: addressType,
+		})
+
 	// Here we generate a final delivery address in bob's wallet but set by
 	// alice. We do this to ensure that the address is not in alice's LND
 	// wallet. We already correctly track settled balances when the address
 	// is in the LND wallet.
-	addr := bob.RPC.NewAddress(&lnrpc.NewAddressRequest{
-		Type: deliveryAddressType,
-	})
+	default:
+		res := bob.RPC.NewAddress(&lnrpc.NewAddressRequest{
+			Type: deliveryAddressType,
+		})
+		addr = res.Address
+	}
 
 	// Prepare for channel open.
 	openParams := lntest.OpenChannelParams{
@@ -76,7 +214,7 @@ func testCoopCloseWithExternalDelivery(ht *lntest.HarnessTest,
 	// If we are testing the case where we set it on open then we'll set the
 	// upfront shutdown script in the channel open parameters.
 	if upfrontShutdown {
-		openParams.CloseAddress = addr.Address
+		openParams.CloseAddress = addr
 	}
 
 	// Open the channel!
@@ -91,14 +229,14 @@ func testCoopCloseWithExternalDelivery(ht *lntest.HarnessTest,
 	// If we are testing the case where we set the delivery address on
 	// channel close then we will set it in the channel close parameters.
 	if !upfrontShutdown {
-		closeParams.DeliveryAddress = addr.Address
+		closeParams.DeliveryAddress = addr
 	}
 
 	// Close the channel!
 	closeClient := alice.RPC.CloseChannel(&closeParams)
 
 	// Assert that we got a channel update when we get a closing txid.
-	_, err := closeClient.Recv()
+	_, err = closeClient.Recv()
 	require.NoError(ht, err)
 
 	// Mine the closing transaction.