feat(enc.b64): ensure compat with stdlib

enc_b64.go

@@ -6,11 +6,10 @@ import "encoding/base64"
 //
 // Same as encoding/json, base64.StdEncoding or RFC 4648.
 func (e *Encoder) Base64(data []byte) {
-	if len(data) == 0 {
+	if data == nil {
 		e.Null()
 		return
 	}
-
 	e.byte('"')
 	encodedLen := base64.StdEncoding.EncodedLen(len(data))
 	start := len(e.buf)

enc_b64_test.go

@@ -25,10 +25,19 @@ func TestEncoder_Base64(t *testing.T) {
 			requireCompat(t, e.Bytes(), s)
 		}
 	})
-	t.Run("Zero", func(t *testing.T) {
-		var e Encoder
-		e.Base64([]byte{})
-		require.Equal(t, `null`, e.String())
+	t.Run("Zeroes", func(t *testing.T) {
+		t.Run("Nil", func(t *testing.T) {
+			v := []byte(nil)
+			var e Encoder
+			e.Base64(v)
+			requireCompat(t, e.Bytes(), v)
+		})
+		t.Run("ZeroLen", func(t *testing.T) {
+			v := make([]byte, 0)
+			var e Encoder
+			e.Base64(v)
+			requireCompat(t, e.Bytes(), v)
+		})
 	})
 }
 

jx_test.go

@@ -11,11 +11,11 @@ import (
 )
 
 // requireCompat fails if `encoding/json` will encode v differently than exp.
-func requireCompat(t testing.TB, exp []byte, v interface{}) {
+func requireCompat(t testing.TB, got []byte, v interface{}) {
 	t.Helper()
 	buf, err := json.Marshal(v)
 	require.NoError(t, err)
-	require.Equal(t, exp, buf)
+	require.Equal(t, buf, got)
 }
 
 func TestPutEncoder(t *testing.T) {