How do I change my site time to test my recurring payments? I am testing the recurring framework in Drupal commerce on my local mamp environment and I want to test the recurring payments. How to I trick my Drupal site into thinking it's a day later so it will trigger the recurring payment?
If you are working with 5.3+ you can do a trick with namespaces: implementing a new time() function inside your current namespace and create a shared resource where you set the return value in your tests.

You can found a complete description in this blog post: 

PHP: “Mocking” built-in functions like time() in Unit Tests