sessions_are_dying_controller_test.rb

require 'test_helper'

class SessionsAreDyingControllerTest < ActionController::TestCase

  setup
    super
    @user = Factory(:user)
  end

  context 'a signed-in user' do
    setup { @controller.session[:current_user_id] = @user.id }

    context 'updating her own page' do
      setup do
        @old_session = @controller.session
        assert_equal @user.id, old_session[:current_user_id]   # works great!
        post :update, :id => @user, :user => { :some => 'user params' }
      end
      should 'stay signed-in' do
        assert_equal @user.id, @controller.session[:current_user_id] # RAR!!!
      end
      should 'keep the session around' do
        assert_equal @old_session.object_id, @controller.session.object_id # also RAR!!!
      end
    end
 
  end

end

test_helper.rb

require 'shoulda'
require 'factory_girl'

# ensure controllers have sessions so we can sign in
# before making requests:
ActionController::TestCase.class_eval do
  def setup
    @controller.session ||= HashWithIndifferentAccess.new
  end
end