In automated testing, test oracles are used to determine whether software behaves correctly on individual tests by comparing expected behavior with actual behavior, revealing incorrect behavior. Automatically creating test oracles is a challenging task, especially in domains where software behavior is difficult to model. Mobile apps are one such domain, primarily due to their event-driven, GUI-based nature, coupled with significant ecosystem fragmentation. This paper takes a step toward automating the construction of GUI-based test oracles for mobile apps, first by characterizing common behaviors associated with failures into a behavioral taxonomy, and second by using this taxonomy to create automated oracles. Our taxonomy identifies and categorizes common GUI element behaviors, expected app responses, and failures from 124 reproducible bug reports, which allow us to better understand oracle characteristics. We use the taxonomy to create app-independent oracles and report on their generalizability by analyzing an additional dataset of 603 bug reports. We also use this taxonomy to define an app-independent process for creating automated test oracles, which leverages computer vision and natural language processing, and apply our process to automate five types of app-independent oracles. We perform a case study to assess the effectiveness of our automated oracles by exposing them to 15 real-world failures. The oracles reveal 11 of the 15 failures and report only one false positive. Additionally, we combine our oracles with a recent automated test input generation tool for Android, revealing two bugs with a low false positive rate. Our results can help developers create stronger automated tests that can reveal more problems in mobile apps and help researchers who can use the understanding from the taxonomy to make further advances in test automation.

With the increasing use of mobile applications in today's digital world, touch-based graphical user interfaces (GUIs) have become a crucial component of modern software by which end-users carry out computing tasks. As such, the tools involved in creating these GUIs are of fundamental importance. Due to the continuous pressure for frequent releases of mobile apps to keep pace with platform and device updates, the practice of evolving app GUIs is central to mobile app maintenance. Currently, developers manually introduce GUI changes to their apps as they evolve in a time-consuming process that involves creating mock-ups of updated GUIs and then implementing the changes stipulated by the mock-up.

Software maintenance constitutes a large portion of the software development lifecycle. To carry out maintenance tasks, developers often need to understand and reproduce bug reports. As such, there has been increasing research activity coalescing around the notion of automating various activities related to bug reporting. A sizable portion of this research interest has focused on the domain of mobile apps. However, as research around mobile app bug reporting progresses, there is a clear need for a manually vetted and reproducible set of real-world bug reports that can serve as a benchmark for future work. This paper presents AndroR2: a dataset of 90 manually reproduced bug reports for Android apps listed on Google Play and hosted on GitHub, systematically collected via an in-depth analysis of 459 reports extracted from the GitHub issue tracker. For each reproduced report, AndroR2 includes the original bug report, an apk file for the buggy version of the app, an executable reproduction script, and metadata regarding the quality of the reproduction steps associated with the original report. We believe that the AndroR2 dataset can be used to facilitate research in automatically analyzing, understanding, reproducing, localizing, and fixing bugs for mobile applications as well as other software maintenance activities more broadly.

GUI-based models extracted from Android app execution traces, events, or source code can be extremely useful for challenging tasks such as the generation of scenarios or test cases. However, extracting effective models can be an expensive process. Moreover, existing approaches for automatically deriving GUI-based models are not able to generate scenarios that include events which were not observed in execution (nor event) traces. In this paper, we address these and other major challenges in our novel hybrid approach, coined as MONKEYLAB. Our approach is based on the Record→Mine→Generate→Validate framework, which relies on recording app usages that yield execution (event) traces, mining those event traces and generating execution scenarios using statistical language modeling, static and dynamic analyses, and validating the resulting scenarios using an interactive execution of the app on a real device. The framework aims at mining models capable of generating feasible and fully replayable (i.e., Actionable) scenarios reflecting either natural user behavior or uncommon usages (e.g., Corner cases) for a given app. We evaluated MONKEYLAB in a case study involving several medium-to-large open-source Android apps. Our results demonstrate that MONKEYLAB is able to mine GUI-based models that can be used to generate actionable execution scenarios for both natural and unnatural sequences of events on Google Nexus 7 tablets.