You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: type_test.go
    path of file: ./repos/Xray-core/common
    
    the code of the file until where you have to start completion: package common_test

import (
	"context"
	"testing"

	. "github.com/xtls/xray-core/common"
)

type TConfig struct {
	value int
}

type YConfig struct {
	value string
}

func TestObjectCreation(t *testing.T) {
	f := func(ctx context.Context, t interface{}) (interface{}, error) {
		return func() int {
			return t.(*TConfig).val
    
func TestObjectCreation(t *testing.T) {
	f := func(ctx context.Context, t interface{}) (interface{}, error) {
		return func() int {
			return t.(*TConfig).value
		}, nil
	}

	Must(RegisterConfig((*TConfig)(nil), f))
	err := RegisterConfig((*TConfig)(nil), f)
	if err == nil {
		t.Error("expect non-nil error, but got nil")
	}

	g, err := CreateObject(context.Background(), &TConfig{value: 2})
	Must(err)
	if v := g.(func() int)(); v != 2 {
		t.Error("expect return value 2, but got ", v)
	}

	_, err = CreateObject(context.Background(), &YConfig{value: "T"})
	if err == nil {
		t.Error("expect non-nil error, but got nil")
	}
}