We've talked about Testdroid a few times here at AP. There's a good reason for that: it simplifies developers' lives and essentially automates the testing process by running their application or game on over 280 real Android devices (so it's not a virtualized environment). While the service itself aims to make devs' lives easier, Testdroid realized that the pay-as-you-go payment option simply wasn't working for most users. Why? Because problems happen.
The life of a mobile application developer is a tedious one – they're not only responsible for building apps but also ensuring they work on as many of the 900 million Google-certified Android devices that have been activated over the last five years as possible. Of course, Android OS versions start to die out over time, and new versions – along with new handsets – emerge, making this a never-ending cycle of test-update-test-update.