How to write a unit test for getting data from Core Data when UIApplicationSignificantTimeChangeNotification is received

I have a table view which holds data for the current date.
When the day change (UIApplicationSignificantTimeChangeNotification event is received) , I want to empty the table and I am doing this by making a request to Core Data to get the elements based on the new date (no data exist for this).

But I am having trouble writing a unit test for this.

How can I simulate this ?