Faking out for MVC thanks to Stephen Walther : http://stephenwalther.com/archive/2008/07/01/asp-net-mvc-tip-12-faking-the-controller-context

FakeControllerContext.cs

 public class FakeControllerContext : ControllerContext
    {
        public FakeControllerContext(IController controller)
            : this(controller, null, null, null, null, null, null)
        {
        }

        public FakeControllerContext(IController controller, HttpCookieCollection cookies)
            : this(controller, null, null, null, null, cookies, null)
        {
        }

        public FakeControllerContext(IController controller, SessionStateItemCollection sessionItems)
            : this(controller, null, null, null, null, null, sessionItems)
        {
        }


        public FakeControllerContext(IController controller, NameValueCollection formParams)
            : this(controller, null, null, formParams, null, null, null)
        {
        }
        
        public FakeControllerContext(IController controller, NameValueCollection formParams, NameValueCollection queryStringParams)
            : this(controller, null, null, formParams, queryStringParams, null, null)
        {
        }
        
        public FakeControllerContext(IController controller, string userName)
            : this(controller, userName, null, null, null, null, null)
        {
        }
        
        public FakeControllerContext(IController controller, string userName, string[] roles)
            : this(controller, userName, roles, null, null, null, null)
        {
        }
        
        public FakeControllerContext
            (
                IController controller,
                string userName,
                string[] roles,
                NameValueCollection formParams,
                NameValueCollection queryStringParams,
                HttpCookieCollection cookies,
                SessionStateItemCollection sessionItems
            )
            : base(new FakeHttpContext(new FakePrincipal(new FakeIdentity(userName), roles), formParams, queryStringParams, cookies, sessionItems), new RouteData(), controller)
        { }
    }

FakeHttpContext.cs

public class FakeHttpContext : HttpContextBase
    {
        private readonly FakePrincipal _principal;
        private readonly NameValueCollection _formParams;
        private readonly NameValueCollection _queryStringParams;
        private readonly HttpCookieCollection _cookies;
        private readonly SessionStateItemCollection _sessionItems;

        public FakeHttpContext(FakePrincipal principal, NameValueCollection formParams, NameValueCollection queryStringParams, HttpCookieCollection cookies, SessionStateItemCollection sessionItems)
        {
            _principal = principal;
            _formParams = formParams;
            _queryStringParams = queryStringParams;
            _cookies = cookies;
            _sessionItems = sessionItems;
        }

        public override HttpRequestBase Request
        {
            get { return new FakeHttpRequest(_formParams, _queryStringParams, _cookies); }
        }

        public override IPrincipal User
        {
            get { return _principal; }
            set { throw new System.NotImplementedException(); }
        }

        public override HttpSessionStateBase Session
        {
            get { return new FakeHttpSessionState(_sessionItems); }
        }
    }

FakeHttpRequest.cs

public class FakeHttpRequest : HttpRequestBase
    {
        private readonly NameValueCollection _formParams;
        private readonly NameValueCollection _queryStringParams;
        private readonly HttpCookieCollection _cookies;

        public FakeHttpRequest(NameValueCollection formParams, NameValueCollection queryStringParams, HttpCookieCollection cookies)
        {
            _formParams = formParams;
            _queryStringParams = queryStringParams;
            _cookies = cookies;
        }

        public override NameValueCollection Form
        {
            get { return _formParams; }
        }

        public override NameValueCollection QueryString
        {
            get { return _queryStringParams; }
        }

        public override HttpCookieCollection Cookies
        {
            get { return _cookies; }
        }
    }

FakeHttpSessionState.cs

    public class FakeHttpSessionState : HttpSessionStateBase
    {
        private readonly SessionStateItemCollection _sessionItems;

        public FakeHttpSessionState(SessionStateItemCollection sessionItems)
        {
            _sessionItems = sessionItems;
        }

        public override void Add(string name, object value)
        {
            _sessionItems[name] = value;
        }

        public override int Count
        {
            get { return _sessionItems.Count; }
        }

        public override IEnumerator GetEnumerator()
        {
            return _sessionItems.GetEnumerator();
        }

        public override NameObjectCollectionBase.KeysCollection Keys { get { return _sessionItems.Keys; } }

        public override object this[string name]
        {
            get { return _sessionItems[name]; }
            set { _sessionItems[name] = value; }
        }

        public override object this[int index]
        {
            get { return _sessionItems[index]; }
            set { _sessionItems[index] = value; }
        }

        public override void Remove(string name)
        {
            _sessionItems.Remove(name);
        }
    }

FakeIdentity.cs

    public class FakeIdentity : IIdentity
    {
        private readonly string _name;

        public FakeIdentity(string userName)
        {
            _name = userName;
            }

        public string AuthenticationType
        {
            get { throw new NotImplementedException(); }
        }

        public bool IsAuthenticated
        {
            get { return !String.IsNullOrEmpty(_name); }
        }

        public string Name
        {
            get { return _name; }
        }
    }

FakePrincipal.cs

    public class FakePrincipal : IPrincipal
    {
        private readonly IIdentity _identity;
        private readonly string[] _roles;

        public FakePrincipal(IIdentity identity, string[] roles)
        {
            _identity = identity;
            _roles = roles;
        }

        public IIdentity Identity
        {
            get { return _identity; }
        }

        public bool IsInRole(string role)
        {
            return _roles != null && _roles.Contains(role);
        }
    }