Including PHP files doesn't work in Cron PHP Scripts

I am using Ubuntu 14.04 X64.

I am setting up a basic Cron job with crontab -e:

* * * * * /usr/bin/php /var/www/html/test/test.php >> /var/www/cron/cron.log 

This is /var/www/test/test.php:

<?php 
include "../test2.php"; 
?> 

And /var/www/test2.php:

<?php 
echo "hello world"; 
?> 

And yet nothing is being echoed. But when I go to [domain]/test/test.php, I do see “hello world” being echoed. Why am I not seeing it in /var/www/cron/cron.log?