1--TEST-- 2SPL: DoublyLinkedList: Queues 3--FILE-- 4<?php 5$queue = new SplQueue(); 6// errors 7try { 8 $queue->dequeue(); 9} catch (RuntimeException $e) { 10 echo "Exception: ".$e->getMessage()."\n"; 11} 12try { 13 $queue->shift(); 14} catch (RuntimeException $e) { 15 echo "Exception: ".$e->getMessage()."\n"; 16} 17 18// data consistency 19$a = 2; 20$queue->enqueue($a); 21echo $queue->dequeue()."\n"; 22 23// peakable 24$queue->enqueue(1); 25$queue->enqueue(2); 26echo $queue->top()."\n"; 27 28// iterable 29foreach ($queue as $elem) { 30 echo "[$elem]\n"; 31} 32 33// countable 34$queue->enqueue(NULL); 35$queue->enqueue(NULL); 36echo count($queue)."\n"; 37echo $queue->count()."\n"; 38var_dump($queue->dequeue()); 39var_dump($queue->dequeue()); 40 41// clonable 42$queue->enqueue(2); 43$queue_clone = clone $queue; 44$queue_clone->dequeue(); 45echo count($queue)."\n"; 46?> 47--EXPECT-- 48Exception: Can't shift from an empty datastructure 49Exception: Can't shift from an empty datastructure 502 512 52[1] 53[2] 544 554 56int(1) 57int(2) 583 59