Question

I am trying to write a unit test for our log out method. Among other things it FormsAuthentication.SignOut(). However, it throws a System.NullReferenceException.

I’ve created a mock; HttpContext (using Moq), but it is obviously missing something.

My mock context contains:

• A mocked HttpRequestBase on Request
• A mocked HttpResponseBase on Response
• With a HttpCookieCollection on Request.Cookies and another on Response.Cookies
• A mocked IPrincipal on User

I am aware I could go the wrapper route and inject an empty FormsAuth wrapper object in it’s place, but I would really like to avoid the 3 additional files just to fix one line of code. That and I am still curious for an answer

So my question is “What is needed in the HttpContext to allow FormsAuthentication.SignOut() to execute.“

Answer 1

Here’s the code for signout.

public static void SignOut()
{
    Initialize();
    HttpContext current = HttpContext.Current;
    bool flag = current.CookielessHelper.DoesCookieValueExistInOriginal('F');
    current.CookielessHelper.SetCookieValue('F', null);
    if (!CookielessHelperClass.UseCookieless(current, false, CookieMode) || current.Request.Browser.Cookies)
    {
        string str = string.Empty;
        if (current.Request.Browser["supportsEmptyStringInCookieValue"] == "false")
        {
            str = "NoCookie";
        }
        HttpCookie cookie = new HttpCookie(FormsCookieName, str);
        cookie.HttpOnly = true;
        cookie.Path = _FormsCookiePath;
        cookie.Expires = new DateTime(0x7cf, 10, 12);
        cookie.Secure = _RequireSSL;
        if (_CookieDomain != null)
        {
            cookie.Domain = _CookieDomain;
        }
        current.Response.Cookies.RemoveCookie(FormsCookieName);
        current.Response.Cookies.Add(cookie);
    }
    if (flag)
    {
        current.Response.Redirect(GetLoginPage(null), false);
    }
}

Looks like you need a CookielessHelperClass instance. Too bad it’s internal and sealed – there’s no way to mock it unless you’re using TypeMock. +1 for wrapper suggestions 🙂