单元测试Web Api 2设置cookie值

Question

在我的api控制器中，我访问cookie值：

public class SampleController : ApiController
{
    protected int? GetUserFromCookie()
    {
        if (HttpContext.Current.Request.Cookies["User"] != null)
        {
            //do something
        }
     }
}

我为此创建单元测试并尝试执行以下操作：

var httpRequest = new HttpRequest("", "http://stackoverflow/", "");
var stringWriter = new System.IO.StringWriter();
var httpResponce = new HttpResponse(stringWriter);
var httpContext = new HttpContext(httpRequest, httpResponce);
HttpContext.Current = httpContext;

但是HttpContext.Current仍然是空的。 有什么想法吗？