How can I inject something into the session when unit testing a service

I have written a service that reads a CAS session variable ...

package cp


import edu.yale.its.tp.cas.client.filter.CASFilter
import javax.servlet.http.HttpSession
import org.springframework.web.context.request.RequestContextHolder

class AuthorizeService {

 def username
 def loginError
 def permissions

 def authCheck( String pageController, String pageAction ) {

  username = getSession().getAttribute(CASFilter.CAS_FILTER_USER)

.....
Omitted the rest of this to save space.  
.....

 }

 private HttpSession getSession() {
  return RequestContextHolder.currentRequestAttributes().getSession()
 }

I cannot figure out how to put something into the session in my test so that this piece of code will run.

Here's the test:

package cp

import grails.test.*

    class AuthorizeServiceTests extends GroovyTestCase {

     def AuthorizeService

     protected void setUp() {
      super.setUp()
     }

     protected void tearDown() {
      super.tearDown()
     }

     void testAuthCheck() {

      def isAuthorized

      // No username in the session
       isAuthorized = AuthorizeService.authCheck( 'welcome', 'index' )
       assertEquals false, isAuthorized

      // Mock the username to the rest of the 开发者_运维问答tests work
       mockSession["CASFilter.CAS_FILTER_USER"] = "testUser" 


    .....
    Omitted the rest of this to save space.  
    .....

     }

When I run my test, here's the error I get back:

No such property: mockSession for class: cp.AuthorizeServiceTests groovy.lang.MissingPropertyException: No such property: mockSession for class: cp.AuthorizeServiceTests at cp.AuthorizeServiceTests.testAuthCheck(AuthorizeServiceTests.groovy:26)

I've been searching Google for 2 days now trying to find a way to inject something into mockSession or something similar so that I can test this service. I can see where it would be pretty easy to test this if this were a controller, but it appears that services are a whole different animal.

As a bit of background, I'm porting a working PHP application to Grails ... I'm a PHP guy, and this is my first forray into Grails, so I apologize if this is a noob question.

Grails 2.3.4:

import grails.util.GrailsWebUtil

class SomeTests extends GroovyTestCase {

    void testSomething() {
        def request = GrailsWebUtil.bindMockWebRequest()
        def myDummyObject = new DummyObject()
        request.session['myDummyObject'] = myDummyObject

        // Run your code and make asserts
    }
}

take a look at MockUtils

also try ControllerUnitTestCase