Unit Testing Framework for Sharepoint

Hi,
I am trying to test my custom code ( SharePoint 2010),I did some Google and found 2 solution one is official from Microsoft and Other is TypeMock (Paid Solution).
but Microsoft is limit to VS2012 ultimate and I am usingVS2012 Premium.

Type Mock I can't use it because of not free.

Please advice me unit testing frameworks(community contribution) for SharePoint.

Thanks

Nazish Ali Rizvi