fixup! sphinx_test: onion message packet creation

Author: gijswijs

sphinx_test.go

@@ -5,6 +5,7 @@ import (
 	"crypto/rand"
 	"encoding/hex"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"io"
 	"os"
@@ -40,6 +41,14 @@ var (
 	testLegacyRouteNumHops = 20
 )
 
+// Static errors used in tests.
+var (
+	// ErrInsufficientHops is returned when there are not enough hops to
+	// create a route.
+	ErrInsufficientHops = errors.New("at least 2 hops are required to " +
+		"create an onion message route")
+)
+
 // encodeTLVRecord encodes a TLV record with the given type and value.
 func encodeTLVRecord(recordType uint64, value []byte) []byte {
 	var buf bytes.Buffer
@@ -58,19 +67,20 @@ func encodeTLVRecord(recordType uint64, value []byte) []byte {
 
 // writeVarInt writes a variable-length integer to the buffer.
 func writeVarInt(buf *bytes.Buffer, n uint64) {
-	if n < 0xfd {
+	switch {
+	case n < 0xfd:
 		buf.WriteByte(byte(n))
-	} else if n <= 0xffff {
+	case n <= 0xffff:
 		buf.WriteByte(0xfd)
 		buf.WriteByte(byte(n))
 		buf.WriteByte(byte(n >> 8))
-	} else if n <= 0xffffffff {
+	case n <= 0xffffffff:
 		buf.WriteByte(0xfe)
 		buf.WriteByte(byte(n))
 		buf.WriteByte(byte(n >> 8))
 		buf.WriteByte(byte(n >> 16))
 		buf.WriteByte(byte(n >> 24))
-	} else {
+	default:
 		buf.WriteByte(0xff)
 		buf.WriteByte(byte(n))
 		buf.WriteByte(byte(n >> 8))
@@ -385,19 +395,19 @@ func TestTLVPayloadMessagePacket(t *testing.T) {
 	jsonBytes, err := os.ReadFile(testOnionMessageFileName)
 	require.NoError(t, err)
 
-	// Once we have the raw file, we'll unpack it into our jsonTestCase
-	// struct defined above.
+	// Once we have the raw file, we'll unpack it into our
+	// onionMessageJsonTestCase struct defined in path_test.go.
 	testCase := &onionMessageJsonTestCase{}
 	require.NoError(t, json.Unmarshal(jsonBytes, testCase))
 
 	// Next, we'll populate a new OnionHop using the information included
 	// in this test case.
 	var route PaymentPath
 	for i, hop := range testCase.Route.Hops {
-		pubKeyBytes, err := hex.DecodeString(hop.BlindedNodeID)
+		blindedPKbytes, err := hex.DecodeString(hop.BlindedNodeID)
 		require.NoError(t, err)
 
-		pubKey, err := btcec.ParsePubKey(pubKeyBytes)
+		blindedPubKey, err := btcec.ParsePubKey(blindedPKbytes)
 		require.NoError(t, err)
 
 		encryptedRecipientData, err := hex.DecodeString(
@@ -418,8 +428,9 @@ func TestTLVPayloadMessagePacket(t *testing.T) {
 		b.Write(encodeTLVRecord(4, encryptedRecipientData))
 
 		route[i] = OnionHop{
-			NodePub: *pubKey,
+			NodePub: *blindedPubKey,
 			HopPayload: HopPayload{
+				// Onion messages always use TLV payloads.
 				Type:    PayloadTLV,
 				Payload: b.Bytes(),
 			},
@@ -1162,7 +1173,7 @@ const (
 	testTLVFileName = "testdata/onion-test.json"
 
 	// testOnionMessageFileName is the name of the onion message test file.
-	testOnionMessageFileName = "testdata/blinded-onion-message-onion-test.json"
+	testOnionMessageFileName = "testdata/blinded-onion-message-onion-test.json" //nolint:lll
 )
 
 type jsonHop struct {