Malicious code?

Hello!
Thanks for reporting. We will check this file.
But it is a file to perform software tests, probably we will remove it, but it is not a vulnerability or something like that, it’s a file from a known and widely employed Twig library – https://twig.sensiolabs.org/ – and here is the official file in the library – https://github.com/twigphp/Twig/blob/1.x/lib/Twig/Test/IntegrationTestCase.php

So don’t worry, everything is okay.