use error definitions

internal/decoding/decoding.go

@@ -24,7 +24,7 @@ func Decode(data []byte, v interface{}, asArray bool) error {
 	}
 	rv := reflect.ValueOf(v)
 	if rv.Kind() != reflect.Ptr {
-		return fmt.Errorf("%w. v.(type): %t", def.ErrReceiverNotPointer, v)
+		return fmt.Errorf("%w. v.(type): %T", def.ErrReceiverNotPointer, v)
 	}
 
 	rv = rv.Elem()

internal/stream/decoding/decoding.go

@@ -20,11 +20,11 @@ type decoder struct {
 // the result into the pointer of v.
 func Decode(r io.Reader, v interface{}, asArray bool) error {
 	if r == nil {
-		return fmt.Errorf("reader is nil")
+		return def.ErrNoData
 	}
 	rv := reflect.ValueOf(v)
 	if rv.Kind() != reflect.Ptr {
-		return fmt.Errorf("holder must set pointer value. but got: %t", v)
+		return fmt.Errorf("%w. v.(type): %T", def.ErrReceiverNotPointer, v)
 	}
 
 	rv = rv.Elem()

internal/stream/decoding/decoding_test.go

@@ -87,8 +87,13 @@ func TestDecoding(t *testing.T) {
 	t.Run("nil reader", func(t *testing.T) {
 		v := new(int)
 		err := Decode(nil, v, false)
-		tu.Error(t, err)
-		tu.Equal(t, err.Error(), "reader is nil")
+		tu.IsError(t, err, def.ErrNoData)
+	})
+	t.Run("not pointer", func(t *testing.T) {
+		v := 0
+		r := tu.NewTestReader([]byte{def.PositiveFixIntMax})
+		err := Decode(r, v, false)
+		tu.IsError(t, err, def.ErrReceiverNotPointer)
 	})
 }
 

msgpack_test.go

@@ -1496,7 +1496,7 @@ func TestPointer(t *testing.T) {
 			var r int
 			t.Run(u.name, func(t *testing.T) {
 				err := u.u([]byte{def.Nil}, r)
-				ErrorContains(t, err, "holder must set pointer value. but got:")
+				ErrorContains(t, err, "receiver not pointer")
 			})
 		}
 	})