/**
  * @expectedException DoubleLinkedListException
  */
 public function testExceptionEmptyReverse()
 {
     $list = new DoubleLinkedList();
     $list->reverse();
 }
// test the double linked list
<?php 
require 'ListNode.php';
require 'DoubleLinkedList.php';
$dll = new DoubleLinkedList();
$dll->add(4);
//echo "valid call " . $dll->valid("current") . "\r\n";
$dll->add(1);
print 'first : ' . $dll->first() . "\r\n";
$dll->add(5);
$dll->add(15);
$dll->add(25);
$dll->add(35);
$dll->add(45);
$dll->add(10);
$dll->add(10);
// don't allow duplicates.
print 'last  : ' . $dll->last() . "\r\n";
print 'current : ' . $dll->current() . "\r\n";
print 'Count : ' . $dll->count() . "\r\n";
$node = $dll->firstNode();
while ($node != null) {
    print $node->data . "\r\n";
    $node = $node->next;
}
$dll->reverse();
// this just allows reverse access to parts of the list.
$dll->reverseList();
print "Reverse the List : \r\n";
$aNode = $dll->firstNode();
while ($aNode != null) {