1. Automatic and Scalable Fault Detection for Mobile Applications MobiSys’ 14 Presented by Haocheng Huang huanghc@emnets.org

2. Goal  Build a scalable, easy to use system that tests mobile apps for common, externally-inducible faults as thoroughly as possible.  Does not detect all app failures

3. Analyse Root Cause of Crashes  Partition crash reports that we believe originate due to the same root cause into a collection called a crash bucket.  Use two techniques to determine the likely root cause of its crashes  Use data mining techniques  Search various Windows Phone developer forums

4. VarnaSena Architecture

5. Monkey design

6. UI Automator  Two decisions  what UI control to interact with next  how long to wait before picking the next control  Problems in usual design  multiple controls often lead to the same next page  some controls do not have any event handlers attached to them  a systematic exploration can lead to dead ends  Address the first two issues using hit testing, the third by running multiple independent random monkeys concurrently

7. UI Automator Hit Testing  The instrumentation framework instruments all UI event handlers in an app with a hit test monitor.  It also assigns each event handler a unique ID.

8. UI Automator When to interact next?  Add a transaction tracker that monitors the transaction at runtime and generates a ProcessingCompleted event when all the synchronous and asynchronous processing associated with an interaction is complete

9. UI Automator work flow

10. Inducing Faults  Built as an extensible module in which various fault inducing modules (FIM) can be plugged in.

11. Evaluation  VanarSena flagged 2969 unique crashes3 in 1108 apps.

12. Evaluation  Found 1,227 crashes not in the WPER database

13. Evaluation

14. Conclusion