I am writing a scheduled class for sending emails for user who have not logged in to salesforce for 30 days, Code is working fine but now I am confused how to write test classes for that, Because all of my conditions are based on Last Login Date which is Un-Editable. Can I take data from a existing user? If i take in such a way will it effect when i move my code to other sandbox/Production? If so how to solve this.

!! Please Help !!

Thanks & Regards
Harsha.