将Xcode 5中的单个XCTest单元测试用例定位到适用于通用应用程序的特定iOS设备？

I'm building a universal iPhone/iPad application, and the UI is significantly different in some cases (i.e. on iPhone we use a Master/Detail paradigm with TableViews, whereas on iPad we're using a CollectionView with cells that contain the details).I'm building a universal iPhone/iPad applicatio