Asp.net web api Can'；t Mock HttpContext.GetOwinContext（）

我正在尝试在登录中实现Auth0 Asp.Net OWIN

我在AccountController上进行单元测试，问题是HTTPContext总是空的 有没有关于如何模拟HttpContext来测试登录名的建议

public class AccountController : Controller
{
    public ActionResult Login(string returnUrl)
    {
        HttpContext.GetOwinContext().Authentication.Challenge(new AuthenticationProperties
            {
                RedirectUri = returnUrl ?? Url.Action("Index", "Home")
            },
            "Auth0");
        return new HttpUnauthorizedResult();
    }

    [Authorize]
    public void Logout()
    {
        HttpContext.GetOwinContext().Authentication.SignOut(CookieAuthenticationDefaults.AuthenticationType);
        HttpContext.GetOwinContext().Authentication.SignOut("Auth0");
    }

    [Authorize]
    public ActionResult Claims()
    {
        return View();
    }
}