问Authlogic/Rspec/Rails3.2: ApplicationController中的UserSession.find返回nil

EN

class User < ActiveRecord::Base 
    acts_as_authentic
end

class UserSession < Authlogic::Session::Base
end

class ApplicationController < ActionController::Base
    helper :all
    protect_from_forgery
    helper_method :current_user_session, :current_user

    private

    def current_user_session
        return @current_user_session if defined?(@current_user_session)
        @current_user_session = UserSession.find
    end

    def current_user
      return @current_user if defined?(@current_user)
      @current_user = current_user_session && current_user_session.record
    end
end

describe "Rate Function" do
    include Authlogic::TestCase
    before(:each) do
        current_user = FactoryGirl.create(:user, persistence_token: "pt", email: "new@example.com", password: 'password', password_confirmation: 'password')
        activate_authlogic
        UserSession.create(current_user)
    end
    it "Some test for rating..." do
        get "/reviews/rate", {:format => :json, :vehicle_id => 3}
        # other stuff here, doesn't matter what it is because it never gets here
    end
    after(:each) do
    end
end

FactoryGirl.define do
    factory :user do
        email "email@example.com"
        password "password"
        password_confirmation "password"
        persistence_token "pertoken"
    end
end

UserSession.create(current_user)
just_created_session = UserSession.find

Ruby: 1.9.3p392
Rails: 3.2.12
Authlogic: 3.2.0
Factory Girl: 4.2.0
Rspec: 2.13.0
OS: Windows 7

def create(*args, &block)
    session = new(*args)
    session.save(&block)
    session
end