Rspec with cookies, testing authentication controller

I am trying use Rspec to test our authentication, this requires me to
set a cookie and pass
it in the header.
when I inspect the headers the cookie is blank
Any ideas why this is not working?

--- The Spec
  it “should redirect to overview page if exists” do
      get ‘login’
        request.session_options[:session_key].should ==
‘_CRS_session_id’
        request.session_options[:secret].should_not == nil
        cookie = request.session_options[:session_key] + ‘=’ +
request.session_options[:secret]
        headers = {
         ‘cookie’ => cookie,
         ‘Referer’ => ‘http://localhost:3000/auth/login’,
         ‘Content-Type’ => ‘application/x-www-form-urlencoded’
        }

        post('login', {:username => 'test', :password => 'password'},
headers)
        puts response.headers["cookie"].inspect
        puts request.inspect

        response.should redirect_to(controller => 'profiles', :action =>
'overview')
  end

-- Controller method for login
  def login
    if request.method == :post && !cookies['_CRS_session_id']
      flash[:auth_error] = :cookies_off
    elsif request.method == :post && params[:login_form]
      username = params[:login_form][:username]
      password = params[:login_form][:password]
      ldap_authenticate(username, password)
    end
  end

--- HTTP RESPONSE

{"Status"=>"200 OK", "ETag"=>"\"4ff001373a428161bc75da425b5dc4be\"",
"X-Runtime"
=>"0.00010", "type"=>"text/html; charset=utf-8", "cookie"=>[],
"Cache-Control"=>
"private, max-age=0, must-revalidate", "Content-Length"=>8140}

--- HTTP REQUEST

#<ActionController::TestRequest:0xf2d026c
@session=#<ActionController::TestSessi
on:0xf2c0a24 @attributes=nil, @session_id="",
@saved_attributes={"cookie"=>"_CRS
_session_id=2887ccde4594cb37332cce1c974962957cf9e102b38155067f175cefbc633e26547c
b4e17c9710a71cf39288560d88a9b8b4b707610c9afddswer5530640",
"Referer"=>"http:
//localhost:3000/auth/login",
"Content-Type"=>"application/x-www-form-urlencoded
"}>, @path=nil, @accepts=nil, @user_agent="Rails Testing",
@env={"REMOTE_ADDR"=>
"0.0.0.0", "REQUEST_URI"=>"/auth/login", "SERVER_PORT"=>80,
"REQUEST_METHOD"=>"P
OST"}, @session_options={:session_key=>"_CRS_session_id",
:secret=>"2887ccde45
94cb37332cce1c974962957cf9e102b38155067f175cefbc633e26547cb4e17c9710a71cf3928856
0d88a9b8b4b707610c9afddswer5530640"}, @cookies={},
@request_method=:post, @req
uest_parameters={:username=>"test", :password=>"password"},
@request_uri=nil, @symb
olized_path_parameters={:action=>"login", :controller=>"auth"},
@query_parameter
s={"action"=>"login"}, @path_parameters={"action"=>"login",
"controller"=>"auth"
}, @content_type=nil, @parameters={"username"=>"test",
"action"=>"login", "cont
roller"=>"auth", "password"=>"password"}, @host="test.host">
...
I've been struggling with this for ages so any input will be greatly
appreciated.
I've also looked at mocks and could not get that to work.
Kevin.