1--TEST-- 2usort() is stable 3--FILE-- 4<?php 5 6$array = range(0, 10000); 7usort($array, function($a, $b) { 8 // Everything is equal! 9 return 0; 10}); 11var_dump($array === range(0, 10000)); 12 13?> 14--EXPECT-- 15bool(true) 16