lntest: allow node restore by extended root key

To allow testing restoring a node from an extended master root key, we
add an extra argument to the RestoreNodeWithSeed function.

lntest/harness.go

@@ -426,7 +426,7 @@ func (n *NetworkHarness) newNodeWithSeed(name string, extraArgs []string,
 // will finish initializing the LightningClient such that the HarnessNode can
 // be used for regular rpc operations.
 func (n *NetworkHarness) RestoreNodeWithSeed(name string, extraArgs []string,
-	password []byte, mnemonic []string, recoveryWindow int32,
+	password []byte, mnemonic []string, rootKey string, recoveryWindow int32,
 	chanBackups *lnrpc.ChanBackupSnapshot,
 	opts ...NodeOption) (*HarnessNode, error) {
 
@@ -441,6 +441,7 @@ func (n *NetworkHarness) RestoreNodeWithSeed(name string, extraArgs []string,
 		WalletPassword:     password,
 		CipherSeedMnemonic: mnemonic,
 		AezeedPassphrase:   password,
+		ExtendedMasterKey:  rootKey,
 		RecoveryWindow:     recoveryWindow,
 		ChannelBackups:     chanBackups,
 	}

lntest/itest/lnd_channel_backup_test.go

@@ -122,8 +122,8 @@ func testChannelBackupRestore(net *lntest.NetworkHarness, t *harnessTest) {
 				// obtained above.
 				return func() (*lntest.HarnessNode, error) {
 					return net.RestoreNodeWithSeed(
-						"dave", nil, password,
+						"dave", nil, password, mnemonic,
-						mnemonic, 1000, backupSnapshot,
+						"", 1000, backupSnapshot,
 						copyPorts(oldNode),
 					)
 				}, nil
@@ -159,8 +159,8 @@ func testChannelBackupRestore(net *lntest.NetworkHarness, t *harnessTest) {
 				// restart it again using Unlock.
 				return func() (*lntest.HarnessNode, error) {
 					newNode, err := net.RestoreNodeWithSeed(
-						"dave", nil, password,
+						"dave", nil, password, mnemonic,
-						mnemonic, 1000, nil,
+						"", 1000, nil,
 						copyPorts(oldNode),
 					)
 					if err != nil {
@@ -208,7 +208,8 @@ func testChannelBackupRestore(net *lntest.NetworkHarness, t *harnessTest) {
 				return func() (*lntest.HarnessNode, error) {
 					newNode, err := net.RestoreNodeWithSeed(
 						"dave", nil, password, mnemonic,
-						1000, nil, copyPorts(oldNode),
+						"", 1000, nil,
+						copyPorts(oldNode),
 					)
 					if err != nil {
 						return nil, fmt.Errorf("unable to "+
@@ -1322,7 +1323,7 @@ func chanRestoreViaRPC(net *lntest.NetworkHarness, password []byte,
 
 	return func() (*lntest.HarnessNode, error) {
 		newNode, err := net.RestoreNodeWithSeed(
-			"dave", nil, password, mnemonic, 1000, nil,
+			"dave", nil, password, mnemonic, "", 1000, nil,
 			copyPorts(oldNode),
 		)
 		if err != nil {

lntest/itest/lnd_recovery_test.go

@@ -34,7 +34,8 @@ func testGetRecoveryInfo(net *lntest.NetworkHarness, t *harnessTest) {
 		// Restore Carol, passing in the password, mnemonic, and
 		// desired recovery window.
 		node, err := net.RestoreNodeWithSeed(
-			"Carol", nil, password, mnemonic, recoveryWindow, nil,
+			"Carol", nil, password, mnemonic, "", recoveryWindow,
+			nil,
 		)
 		if err != nil {
 			t.Fatalf("unable to restore node: %v", err)
@@ -130,6 +131,11 @@ func testOnchainFundRecovery(net *lntest.NetworkHarness, t *harnessTest) {
 	}
 	shutdownAndAssert(net, t, carol)
 
+	// As long as the mnemonic is non-nil and the extended key is empty, the
+	// closure below will always restore the node from the seed. The tests
+	// need to manually overwrite this value to change that behavior.
+	rootKey := ""
+
 	// Create a closure for testing the recovery of Carol's wallet. This
 	// method takes the expected value of Carol's balance when using the
 	// given recovery window. Additionally, the caller can specify an action
@@ -140,7 +146,8 @@ func testOnchainFundRecovery(net *lntest.NetworkHarness, t *harnessTest) {
 		// Restore Carol, passing in the password, mnemonic, and
 		// desired recovery window.
 		node, err := net.RestoreNodeWithSeed(
-			"Carol", nil, password, mnemonic, recoveryWindow, nil,
+			"Carol", nil, password, mnemonic, rootKey,
+			recoveryWindow, nil,
 		)
 		if err != nil {
 			t.Fatalf("unable to restore node: %v", err)