diff --git a/htlcswitch/mock.go b/htlcswitch/mock.go
index dbacaa69..9d3a2938 100644
--- a/htlcswitch/mock.go
+++ b/htlcswitch/mock.go
@@ -13,6 +13,10 @@ import (
 	"testing"
 	"time"
 
+	"github.com/btcsuite/btcd/btcec"
+	"github.com/btcsuite/btcd/chaincfg/chainhash"
+	"github.com/btcsuite/btcd/txscript"
+	"github.com/btcsuite/btcd/wire"
 	"github.com/btcsuite/fastsha256"
 	"github.com/go-errors/errors"
 	"github.com/lightningnetwork/lightning-onion"
@@ -22,10 +26,6 @@ import (
 	"github.com/lightningnetwork/lnd/lnpeer"
 	"github.com/lightningnetwork/lnd/lnwallet"
 	"github.com/lightningnetwork/lnd/lnwire"
-	"github.com/btcsuite/btcd/btcec"
-	"github.com/btcsuite/btcd/chaincfg/chainhash"
-	"github.com/btcsuite/btcd/txscript"
-	"github.com/btcsuite/btcd/wire"
 )
 
 type mockPreimageCache struct {
@@ -800,7 +800,7 @@ func (m *mockNotifier) Stop() error {
 	return nil
 }
 
-func (m *mockNotifier) RegisterSpendNtfn(outpoint *wire.OutPoint,
+func (m *mockNotifier) RegisterSpendNtfn(outpoint *wire.OutPoint, _ []byte,
 	heightHint uint32) (*chainntnfs.SpendEvent, error) {
 
 	return &chainntnfs.SpendEvent{