Let's say I just wrote the following class and I am starting to write some unit tests for it:

<http://www.ogre3d.org/docs/api/html/classOgre_1_1Timer.html>

How would I make sure the timer is working properly by just the unit tests? I can test to make sure that `getMilliseconds()` is always greater than the start time for example, but that does not tell me that `getMilliseconds()` is returning the correct delta-time. 

Any suggestions?