I have written a class to calculate business hours for Case age in business hours.  The class works great my issue is when trying to write decent test code for the class.

In following testing best practices, I want to create all my own test data and not rely on existing data (seeAllDate=true).  I would assume that in order to test my different scenarios I would need to create and insert new business hours.  Normally, I would use something like the snippet below

    BusinessHours newHours = new BusinessHours(
    	MondayStartTime = Time.newInstance(9, 0, 0, 0),
    	MondayEndTime = Time.newInstance(17, 0, 0, 0),
    	TuesdayStartTime = Time.newInstance(9, 0, 0, 0),
    	TuesdayEndTime = Time.newInstance(17, 0, 0, 0),
    	WednesdayStartTime = Time.newInstance(9, 0, 0, 0),
    	WednesdayEndTime = Time.newInstance(17, 0, 0, 0),
    	ThursdayStartTime = Time.newInstance(9, 0, 0, 0),
    	ThursdayEndTime = Time.newInstance(17, 0, 0, 0),
    	FridayStartTime = Time.newInstance(9, 0, 0, 0),
    	FridayEndTime = Time.newInstance(17, 0, 0, 0),
    	IsActive = true,
    	IsDefault = true
    );
    insert newHours;

However, you cannot perform DML on business hours.  Is there a way to do this without having to use seeAllData=true?

I have searched and searched but can;t find much info on using the business hours class in test code.  Any help is much appreciated.