libs/log: format []byte as hexidecimal string (uppercased) (#5960)

Closes: #5806 

Co-authored-by: Lanie Hei <heixx011@umn.edu>

libs/bytes/bytes.go

@@ -8,7 +8,7 @@ import (
 	"strings"
 )
 
-// The main purpose of HexBytes is to enable HEX-encoding for json/encoding.
+// HexBytes enables HEX-encoding for json/encoding.
 type HexBytes []byte
 
 var (
@@ -58,7 +58,7 @@ func (bz *HexBytes) UnmarshalJSON(data []byte) error {
 	return nil
 }
 
-// Allow it to fulfill various interfaces in light-client, etc...
+// Bytes fulfils various interfaces in light-client, etc...
 func (bz HexBytes) Bytes() []byte {
 	return bz
 }
@@ -67,6 +67,9 @@ func (bz HexBytes) String() string {
 	return strings.ToUpper(hex.EncodeToString(bz))
 }
 
+// Format writes either address of 0th element in a slice in base 16 notation,
+// with leading 0x (%p), or casts HexBytes to bytes and writes as hexadecimal
+// string to s.
 func (bz HexBytes) Format(s fmt.State, verb rune) {
 	switch verb {
 	case 'p':

libs/bytes/bytes_test.go

@@ -3,6 +3,7 @@ package bytes
 import (
 	"encoding/json"
 	"fmt"
+	"strconv"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -24,7 +25,6 @@ func TestMarshal(t *testing.T) {
 
 // Test that the hex encoding works.
 func TestJSONMarshal(t *testing.T) {
-
 	type TestStruct struct {
 		B1 []byte
 		B2 HexBytes
@@ -64,3 +64,10 @@ func TestJSONMarshal(t *testing.T) {
 		})
 	}
 }
+
+func TestHexBytes_String(t *testing.T) {
+	hs := HexBytes([]byte("test me"))
+	if _, err := strconv.ParseInt(hs.String(), 16, 64); err != nil {
+		t.Fatal(err)
+	}
+}