I generally set this up so that when I type 'should' I can press tab and it will automatically create an outline of a test method for me.
Creating a template is as simple as going to 'ReSharper > Live Templates' from Visual Studio.
I have attached several templates that I seem to end up writing over and over again.
To import these go to 'ReSharper > Live Templates' and click on the Import button on the menu.
To make class creation templates available on the 'Add New Item From Template' menu right click on the project, 'Add > New From Template > More' then select the appropriate template and tick the box which says 'Add to quicklist'