I often see posts on twitter or software testing communities where people asking for help regarding mobile device fragmentation and how to handle all those different devices. Usually my answer to this is, that you don’t need to test on that many mobile devices.
There are several ways to go. One way to go, is to gather user information from tracking statistics of the released app version. If the app is not yet released, statistics from the Web page (if in place) can help to gather information about the target customers and the devices they are using. If this kind of information is available you can start thinking about how to get at least the top 10 – 15 devices of the customers.