The kind of fragmentation Google has to deal with in developing Android and its framework is very, very different from the kind of fragmentation the average app

The kind of fragmentation Google has to deal with in developing Android and its framework is very, very different from the kind of fragmentation the average app developer deals with. The vast majority of apps only need to test on a couple different device types, all of which can be done via the emulator. Most app developers have trouble with the APIs their apps use that do not behave as expected on some devices, usually as the result of a manufacturer or carrier change that subtly alters the behavior of or breaks the API. Google, OTOH, has a significant amount of testing to do on most Android devices produce. Not only do OS devs need many devices to ensure the OS and framework continues to function, but most (if not all) devices will be run against the Android CTS (http://source.android.com/compatibility/cts-intro.html http://source.android.com/compatibility/cts-intro.html).