CakePHP Controller Tetsing

UsersControllerTest.php

<?php
/* Users Test cases generated on: 2012-03-13 19:59:39 : 1331668779*/
App::uses('UsersController', 'Controller');

/**
 * TestUsersController *
 */
class TestUsersController extends UsersController {
/**
 * Auto render
 *
 * @var boolean
 */
	public $autoRender = false;

/**
 * Redirect action
 *
 * @param mixed $url
 * @param mixed $status
 * @param boolean $exit
 * @return void
 */
	public function redirect($url, $status = null, $exit = true) {
		$this->redirectUrl = $url;
	}
       
}

/**
 * UsersController Test Case
 *
 */
class UsersControllerTestCase extends ControllerTestCase {
/**
 * Fixtures
 *
 * @var array
 */
	public $fixtures = array('app.user', 'app.group');

/**
 * setUp method
 *
 * @return void
 */
	public function setUp() {
		parent::setUp();

		$this->Users = new TestUsersController();
	}

/**
 * tearDown method
 *
 * @return void
 */
	public function tearDown() {
		unset($this->Users);

		parent::tearDown();
	}

/**
 * testAdminIndex method
 *
 * @return void
 */
	public function testAdminIndex() {
        $result = $this->testAction('admin/users/index');
        debug($result);
	}

/**
 * testAdminView method
 *
 * @return void
 */
	public function testAdminView() {

	}

/**
 * testAdminAdd method
 *
 * @return void
 */
	public function testAdminAdd() {

	}

/**
 * testAdminEdit method
 *
 * @return void
 */
	public function testAdminEdit() {

	}

/**
 * testAdminDelete method
 *
 * @return void
 */
	public function testAdminDelete() {

	}

    
}

Th error im getting is:

Undefined index: params
Test case: UsersControllerTestCase(testAdminIndex)

More of the error:

PHPUnit_Framework_Error_Notice
Undefined index: params
Test case: UsersControllerTestCase(testAdminIndex)
Stack trace:
E:\wamp\www\cakephp\lib\Cake\Controller\Component\AuthComponent.php : 719
E:\wamp\www\cakephp\lib\Cake\Controller\Component\AuthComponent.php : 316
AuthComponent::startup
E:\wamp\www\cakephp\lib\Cake\Utility\ObjectCollection.php : 130
ObjectCollection::trigger
E:\wamp\www\cakephp\lib\Cake\Event\CakeEventManager.php : 246
E:\wamp\www\cakephp\lib\Cake\Controller\Controller.php : 671
E:\wamp\www\cakephp\lib\Cake\Routing\Dispatcher.php : 100
E:\wamp\www\cakephp\lib\Cake\Routing\Dispatcher.php : 85
E:\wamp\www\cakephp\lib\Cake\TestSuite\ControllerTestCase.php : 266