assertNotContains incorrectly fails in some cases

[rrehbein]

Code:

<?php
require 'vendor/autoload.php';
PHPUnit_Framework_Assert::assertNotContains(931640626, "2037827403");

Expected:

• no error

Actual:

PHP Fatal error:  Uncaught Failed asserting that '2037827403' does not contain "931640626".

Only some combinations of numbers do it. I'm not sure what the pattern for failure is. The number source is rand().

Tested on:

• PHP 5.4.41 / PHPUnit 4.7.7 / Debian Wheezy x86_64
• PHP 5.4.31 / PHPUnit 4.5.1 / Ubuntu Trusty x86_64