preview_test_spec.rb

        it "should create a new test set" do
          expect { @preview_test.save }.should change(user.test_sets, :count).by(1)
          @preview_test.test_set.tap do |t|
            t.should be_valid
            t.account.should == account
            t.user.should == user
            t.service.should == email_service
          end
        end