lnwire: add encoding/decoding unit tests for UpdateAddHtlc message

lnwire/test_utils.go

@@ -0,0 +1,29 @@
+package lnwire
+
+import (
+	"crypto/rand"
+	"encoding/hex"
+
+	"github.com/btcsuite/btcd/btcec/v2"
+)
+
+// pubkeyFromHex parses a Bitcoin public key from a hex encoded string.
+func pubkeyFromHex(keyHex string) (*btcec.PublicKey, error) {
+	bytes, err := hex.DecodeString(keyHex)
+	if err != nil {
+		return nil, err
+	}
+
+	return btcec.ParsePubKey(bytes)
+}
+
+// generateRandomBytes returns a slice of n random bytes.
+func generateRandomBytes(n int) ([]byte, error) {
+	b := make([]byte, n)
+	_, err := rand.Read(b)
+	if err != nil {
+		return nil, err
+	}
+
+	return b, nil
+}

lnwire/update_add_htlc_test.go

@@ -0,0 +1,216 @@
+package lnwire
+
+import (
+	"bytes"
+	"testing"
+
+	"github.com/lightningnetwork/lnd/tlv"
+	"github.com/stretchr/testify/require"
+)
+
+// testCase is a test case for the UpdateAddHTLC message.
+type testCase struct {
+	// Msg is the message to be encoded and decoded.
+	Msg UpdateAddHTLC
+
+	// ExpectEncodeError is a flag that indicates whether we expect the
+	// encoding of the message to fail.
+	ExpectEncodeError bool
+}
+
+// generateTestCases generates a set of UpdateAddHTLC message test cases.
+func generateTestCases(t *testing.T) []testCase {
+	// Firstly, we'll set basic values for the message fields.
+	//
+	// Generate random channel ID.
+	chanIDBytes, err := generateRandomBytes(32)
+	require.NoError(t, err)
+
+	var chanID ChannelID
+	copy(chanID[:], chanIDBytes)
+
+	// Generate random payment hash.
+	paymentHashBytes, err := generateRandomBytes(32)
+	require.NoError(t, err)
+
+	var paymentHash [32]byte
+	copy(paymentHash[:], paymentHashBytes)
+
+	// Generate random onion blob.
+	onionBlobBytes, err := generateRandomBytes(OnionPacketSize)
+	require.NoError(t, err)
+
+	var onionBlob [OnionPacketSize]byte
+	copy(onionBlob[:], onionBlobBytes)
+
+	// Define the blinding point.
+	blinding, err := pubkeyFromHex(
+		"0228f2af0abe322403480fb3ee172f7f1601e67d1da6cad40b54c4468d4" +
+			"8236c39",
+	)
+	require.NoError(t, err)
+
+	blindingPoint := tlv.SomeRecordT(
+		tlv.NewPrimitiveRecord[BlindingPointTlvType](blinding),
+	)
+
+	// Define custom records.
+	recordKey1 := uint64(MinCustomRecordsTlvType + 1)
+	recordValue1, err := generateRandomBytes(10)
+	require.NoError(t, err)
+
+	recordKey2 := uint64(MinCustomRecordsTlvType + 2)
+	recordValue2, err := generateRandomBytes(10)
+	require.NoError(t, err)
+
+	customRecords := CustomRecords{
+		recordKey1: recordValue1,
+		recordKey2: recordValue2,
+	}
+
+	// Construct an instance of extra data that contains records with TLV
+	// types below the minimum custom records threshold and that lack
+	// corresponding fields in the message struct. Content should persist in
+	// the extra data field after encoding and decoding.
+	var (
+		recordBytes45 = []byte("recordBytes45")
+		tlvRecord45   = tlv.NewPrimitiveRecord[tlv.TlvType45](
+			recordBytes45,
+		)
+
+		recordBytes55 = []byte("recordBytes55")
+		tlvRecord55   = tlv.NewPrimitiveRecord[tlv.TlvType55](
+			recordBytes55,
+		)
+	)
+
+	var extraData ExtraOpaqueData
+	err = extraData.PackRecords(
+		[]tlv.RecordProducer{&tlvRecord45, &tlvRecord55}...,
+	)
+	require.NoError(t, err)
+
+	// Define test cases.
+	testCases := make([]testCase, 0)
+
+	testCases = append(testCases, testCase{
+		Msg: UpdateAddHTLC{
+			ChanID:        chanID,
+			ID:            42,
+			Amount:        MilliSatoshi(1000),
+			PaymentHash:   paymentHash,
+			Expiry:        43,
+			OnionBlob:     onionBlob,
+			BlindingPoint: blindingPoint,
+			CustomRecords: customRecords,
+			ExtraData:     extraData,
+		},
+	})
+
+	// Add a test case where the blinding point field is not populated.
+	testCases = append(testCases, testCase{
+		Msg: UpdateAddHTLC{
+			ChanID:        chanID,
+			ID:            42,
+			Amount:        MilliSatoshi(1000),
+			PaymentHash:   paymentHash,
+			Expiry:        43,
+			OnionBlob:     onionBlob,
+			CustomRecords: customRecords,
+		},
+	})
+
+	// Add a test case where the custom records field is not populated.
+	testCases = append(testCases, testCase{
+		Msg: UpdateAddHTLC{
+			ChanID:        chanID,
+			ID:            42,
+			Amount:        MilliSatoshi(1000),
+			PaymentHash:   paymentHash,
+			Expiry:        43,
+			OnionBlob:     onionBlob,
+			BlindingPoint: blindingPoint,
+		},
+	})
+
+	// Add a case where the custom records are invlaid.
+	invalidCustomRecords := CustomRecords{
+		MinCustomRecordsTlvType - 1: recordValue1,
+	}
+
+	testCases = append(testCases, testCase{
+		Msg: UpdateAddHTLC{
+			ChanID:        chanID,
+			ID:            42,
+			Amount:        MilliSatoshi(1000),
+			PaymentHash:   paymentHash,
+			Expiry:        43,
+			OnionBlob:     onionBlob,
+			BlindingPoint: blindingPoint,
+			CustomRecords: invalidCustomRecords,
+		},
+		ExpectEncodeError: true,
+	})
+
+	return testCases
+}
+
+// TestUpdateAddHtlcEncodeDecode tests UpdateAddHTLC message encoding and
+// decoding for all supported field values.
+func TestUpdateAddHtlcEncodeDecode(t *testing.T) {
+	t.Parallel()
+
+	// Generate test cases.
+	testCases := generateTestCases(t)
+
+	// Execute test cases.
+	for tcIdx, tc := range testCases {
+		t.Log("Running test case", tcIdx)
+
+		// Encode test case message.
+		var buf bytes.Buffer
+		err := tc.Msg.Encode(&buf, 0)
+
+		// Check if we expect an encoding error.
+		if tc.ExpectEncodeError {
+			require.Error(t, err)
+			continue
+		}
+		require.NoError(t, err)
+
+		// Decode the encoded message bytes message.
+		var actualMsg UpdateAddHTLC
+		decodeReader := bytes.NewReader(buf.Bytes())
+		err = actualMsg.Decode(decodeReader, 0)
+		require.NoError(t, err)
+
+		// Compare the two messages to ensure equality one field at a
+		// time.
+		require.Equal(t, tc.Msg.ChanID, actualMsg.ChanID)
+		require.Equal(t, tc.Msg.ID, actualMsg.ID)
+		require.Equal(t, tc.Msg.Amount, actualMsg.Amount)
+		require.Equal(t, tc.Msg.PaymentHash, actualMsg.PaymentHash)
+		require.Equal(t, tc.Msg.OnionBlob, actualMsg.OnionBlob)
+		require.Equal(t, tc.Msg.BlindingPoint, actualMsg.BlindingPoint)
+
+		// Check that the custom records field is as expected.
+		if len(tc.Msg.CustomRecords) == 0 {
+			require.Len(t, actualMsg.CustomRecords, 0)
+		} else {
+			require.Equal(
+				t, tc.Msg.CustomRecords,
+				actualMsg.CustomRecords,
+			)
+		}
+
+		// Check that the extra data field is as expected.
+		if len(tc.Msg.ExtraData) == 0 {
+			require.Len(t, actualMsg.ExtraData, 0)
+		} else {
+			require.Equal(
+				t, tc.Msg.ExtraData,
+				actualMsg.ExtraData,
+			)
+		}
+	}
+}