routing/route: add tests for Vertex TLV encode/decode and invalid length

Author: erickcestari

routing/route/route_test.go

@@ -8,6 +8,7 @@ import (
 	"github.com/btcsuite/btcd/btcec/v2"
 	"github.com/lightningnetwork/lnd/lnwire"
 	"github.com/lightningnetwork/lnd/record"
+	"github.com/lightningnetwork/lnd/tlv"
 	"github.com/stretchr/testify/require"
 )
 
@@ -430,3 +431,52 @@ func TestBlindedHopFee(t *testing.T) {
 	require.Equal(t, lnwire.MilliSatoshi(0), route.HopFee(3))
 	require.Equal(t, lnwire.MilliSatoshi(0), route.HopFee(4))
 }
+
+func makeVertex() Vertex {
+	var v Vertex
+	for i := 0; i < VertexSize; i++ {
+		v[i] = byte(i)
+	}
+	return v
+}
+
+// TestVertexTLVEncodeDecode tests that we're able to properly encode and decode
+// Vertex within TLV streams.
+func TestVertexTLVEncodeDecode(t *testing.T) {
+	t.Parallel()
+
+	vertex := makeVertex()
+
+	var extraData lnwire.ExtraOpaqueData
+	require.NoError(t, extraData.PackRecords(&vertex))
+
+	var vertex2 Vertex
+	tlvs, err := extraData.ExtractRecords(&vertex2)
+	require.NoError(t, err)
+
+	require.Contains(t, tlvs, tlv.Type(0))
+	require.Equal(t, vertex, vertex2)
+}
+
+// TestVertexTypeDecodeInvalidLength ensures that decoding a Vertex TLV
+// with an invalid length (anything other than 33) fails with an error.
+func TestVertexTypeDecodeInvalidLength(t *testing.T) {
+	t.Parallel()
+
+	vertex := makeVertex()
+
+	var extraData lnwire.ExtraOpaqueData
+	require.NoError(t, extraData.PackRecords(&vertex))
+
+	// Corrupt the TLV length field to simulate malformed input.
+	extraData[1] = VertexSize + 1
+
+	var out Vertex
+	_, err := extraData.ExtractRecords(&out)
+	require.Error(t, err)
+
+	extraData[1] = VertexSize - 1
+
+	_, err = extraData.ExtractRecords(&out)
+	require.Error(t, err)
+}