chainfee: add new unit SatPerVByte

lnwallet/chainfee/rates.go

@@ -18,6 +18,24 @@ const (
 	AbsoluteFeePerKwFloor SatPerKWeight = 250
 )
 
+// SatPerVByte represents a fee rate in sat/vbyte.
+type SatPerVByte btcutil.Amount
+
+// FeePerKWeight converts the current fee rate from sat/vb to sat/kw.
+func (s SatPerVByte) FeePerKWeight() SatPerKWeight {
+	return SatPerKWeight(s * 1000 / blockchain.WitnessScaleFactor)
+}
+
+// FeePerKVByte converts the current fee rate from sat/vb to sat/kvb.
+func (s SatPerVByte) FeePerKVByte() SatPerKVByte {
+	return SatPerKVByte(s * 1000)
+}
+
+// String returns a human-readable string of the fee rate.
+func (s SatPerVByte) String() string {
+	return fmt.Sprintf("%v sat/vb", int64(s))
+}
+
 // SatPerKVByte represents a fee rate in sat/kb.
 type SatPerKVByte btcutil.Amount
 

lnwallet/chainfee/rates_test.go

@@ -0,0 +1,22 @@
+package chainfee
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+// TestSatPerVByteConversion checks that the conversion from sat/vb to either
+// sat/kw or sat/kvb is correct.
+func TestSatPerVByteConversion(t *testing.T) {
+	t.Parallel()
+
+	// Create a test fee rate of 1 sat/vb.
+	rate := SatPerVByte(1)
+
+	// 1 sat/vb should be equal to 1000 sat/kvb.
+	require.Equal(t, SatPerKVByte(1000), rate.FeePerKVByte())
+
+	// 1 sat/vb should be equal to 250 sat/kw.
+	require.Equal(t, SatPerKWeight(250), rate.FeePerKWeight())
+}