protected function _listUsers()
{
$users = self::$group->listUsers(self::$groupids[0]);
$this->assertEquals(1, count($users));
$this->assertTrue(in_array('joe', $users));
$users = self::$group->listUsers(self::$groupids[1]);
$this->assertEquals(2, count($users));
$this->assertTrue(in_array('joe', $users));
$this->assertTrue(in_array('jane', $users));
}