1--TEST-- 2Testing interface_exists() 3--FILE-- 4<?php 5 6interface foo { 7} 8 9var_dump(interface_exists('foo')); 10var_dump(interface_exists(1)); 11var_dump(interface_exists(NULL)); 12 13?> 14--EXPECT-- 15bool(true) 16bool(false) 17bool(false) 18