Xdroid: Testing Android Apps with Dependency Injection

The applications ("apps") running on Android need to be adequately tested to avoid faults. Researchers have developed a number of test input generation tools for automated app testing and tried to improve test coverage to detect as many faults as possible. However, existing testing tools achieve very low coverage for some specific apps because they highly depend on external factors to run properly such as business logic, content providers and so on. In this paper, we present Xdroid to catch when and what kind of dependencies apps require and inject them correspondingly in a lightweight way. Working with a built-in tool Xmonkey which generates GUI events directly on Android devices, Xdroid implements an effective testing engine to get a high coverage. We evaluate Xdroid with diverse Android apps and demonstrate that it outperforms Monkey for 17%, Sapienz for 22% in coverage and meanwhile reveals more bugs than manual testing. Overall, it combines the benefits of both manual testing and random testing to improve test coverage and detect bugs effectively.