Unit Testing MVC Controllers

A controller in my ASP.NET MVC application pre-populates form data displayed by my view according to a couple of fairly straight forward rules.

It seems like this would be a good thing to cover in my unit testing. But the only way I could see to verify the correct data is placed in the form, would be to extract the logic from the controller in what feels like an unnatural way.

Can someone suggest ways to approach this?

All the examples I've found of unit testing controllers seemed very trivial, such as verifying it returned the expected type of view. I'm not sure I even see the value in that.