update codec to allow reuse buffers

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

codec_test.go

@@ -4,9 +4,19 @@ import (
 	"bytes"
 	"testing"
 
+	"go.unistack.org/micro/v3/broker"
 	"go.unistack.org/micro/v3/codec"
 )
 
+func TestRawMessage(t *testing.T) {
+	b := &broker.Message{}
+	buf, err := NewCodec().Marshal(b)
+	if err != nil {
+		panic(err)
+	}
+	t.Logf("%s", buf)
+}
+
 func TestFrame(t *testing.T) {
 	s := &codec.Frame{Data: []byte("test")}
 
@@ -28,7 +38,7 @@ func TestFrameFlatten(t *testing.T) {
 		Name: &codec.Frame{Data: []byte("test")},
 	}
 
-	buf, err := NewCodec().Marshal(s)
+	buf, err := NewCodec(codec.Flatten(true)).Marshal(s)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -44,13 +54,13 @@ func TestStructByTag(t *testing.T) {
 
 	val := &Str{Name: []string{"first", "second"}}
 
-	c := NewCodec()
+	c := NewCodec(codec.Flatten(true))
 	buf, err := c.Marshal(val)
 	if err != nil {
 		t.Fatal(err)
 	}
 	if !bytes.Equal(buf, []byte(`["first","second"]`)) {
-		t.Fatalf("invalid marshal: %v != %v", buf, []byte(`["first","second"]`))
+		t.Fatalf("invalid marshal: %s != %s", buf, []byte(`["first","second"]`))
 	}
 
 	err = c.Unmarshal([]byte(`["1","2"]`), val)
@@ -62,15 +72,3 @@ func TestStructByTag(t *testing.T) {
 		t.Fatalf("invalid unmarshal: %v", val)
 	}
 }
-
-func TestReadBody(t *testing.T) {
-	s := &struct {
-		Name string
-	}{}
-	c := NewCodec()
-	b := bytes.NewReader(nil)
-	err := c.ReadBody(b, s)
-	if err != nil {
-		t.Fatal(err)
-	}
-}