When doing functional test, sooner or later you will need to do some testing with cookie, for example when you need to test the infamous ‘Remember me’ functionality.

It is easy to do that in Rails with some points to take note:

To set a cookie in a request:

@request.cookies['name'] = CGI::Cookie.new('name', 'cookie value')

To retrieve a cookie after a response:

cookies['name']

And a sample of Remember Me functional test:

def test_login_with_remember_me
    post :login, :username => 'herry', :password => 'passwd',
        :rememberme => '1'
    assert session[:user]
    assert cookies['auth_token']
    assert_response :redirect
    assert_tag :tag => 'div', 
        :child => /[replace with your error message]/

    # reset user session and set request cookie
    session[:user] = nil
    @request.cookies['auth_token'] = cookies['auth_token']    
  
    get :protected_page
    assert_response :success
    assert session[:user]
end