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1. Freehand Sketching on Smartphones for Teaching Spatial Visualization

   https://doi.org/10.18260/1-2--32859  

   Van Den Einde, Lelli ; Delson, Nathan ; Cowan, Elizabeth ( June 2019 , 2019 ASEE Annual Conference & Exposition)

   Mobile devices are becoming a more common part of the education experience. Students can access their devices at any time to perform assignments or review material. Mobile apps can have the added advantage of being able to automatically grade student work and provide instantaneous feedback. However, numerous challenges remain in implementing effective mobile educational apps. One challenge is the small screen size of smartphones, which was a concern for a spatial visualization training app where students sketch isometric and orthographic drawings. This app was originally developed for iPads, but the wide prevalence of smartphones led to porting the software tomore »iPhone and Android phones. The sketching assignments on a smartphone screen required more frequent zooming and panning, and one of the hypotheses of this study was that the educational effectiveness on smartphones was the same as on the larger screen sizes using iPad tablets. The spatial visualization mobile sketching app was implemented in a college freshman engineering graphics course to teach students how to sketch orthographic and isometric assignments. The app provides automatic grading and hint feedback to help students when they are stuck. Students in this pilot were assigned sketching problems as homework using their personal devices. Students were administered a pre- and post- spatial visualization test (PSVT-R, a reliable, well-validated instrument) to assess learning gains. The trial analysis focuses on students who entered the course with limited spatial visualization experience as identified based on a score of ≤70% on the PSVT:R since students entering college with low PSVT:R scores are at higher risk of dropping out of STEM majors. Among these low-performing students, those who used the app showed significant progress: (71%) raised their test scores above 70% bringing them out of the at-risk range for dropping out of engineering. While the PSVT:R test has been well validated, there are benefits to developing alternative methods of assessing spatial visualization skills. We developed an assembly pre- and post- test based upon a timed Lego™ exercise. At the start of the quarter, students were timed to see how long it would take them to build small lego sets using only visual instructions. Students were timed again on a different lego set after completion of the spatial visualization app. One benefit of the test was that it illustrated to the engineering students a skill that could be perceived as more relevant to their careers, and thus possibly increased their motivation for spatial visualization training. In addition, it may be possible to adapt the assembly test to elementary school grade levels where the PSVT:R test would not be suitable. Preliminary results show that the average lego build times decreased significantly after using the mobile app, indicating an improvement in students’ spatial reasoning skills. A comparison will also be done between normalized completion times on the assembly test and the PSVT:R tests in order to see how the assembly test compares to the “gold standard”. In addition to the PSVT-R instrument, a survey was conducted to evaluate student usage and their impressions of the app. Students found the app engaging, easy to use, and something they would do whenever they had “a free moment”. 95% of the students recommended the app to a friend if they are struggling with spatial visualization skills. This paper will describe the implementation of the mobile spatial visualization sketching app in a large college classroom, and highlight the app’s impact in increasing self-efficacy in spatial visualization and sketching« less
2. An infrastructure approach to improving effectiveness of Android UI testing tools

   https://doi.org/10.1145/3460319.3464828  

   Wang, Wenyu ; Lam, Wing ; Xie, Tao ( July 2021 , 30th ACM SIGSOFT International Symposium on Software Testing and Analysis)

   Due to the importance of Android app quality assurance, many Android UI testing tools have been developed by researchers over the years. However, recent studies show that these tools typically achieve low code coverage on popular industrial apps. In fact, given a reasonable amount of run time, most state-of-the-art tools cannot even outperform a simple tool, Monkey, on popular industrial apps with large codebases and sophisticated functionalities. Our motivating study finds that these tools perform two types of operations, UI Hierarchy Capturing (capturing information about the contents on the screen) and UI Event Execution (executing UI events, such as clicks),more »often inefficiently using UIAutomator, a component of the Android framework. In total, these two types of operations use on average 70% of the given test time. Based on this finding, to improve the effectiveness of Android testing tools, we propose TOLLER, a tool consisting of infrastructure enhancements to the Android operating system. TOLLER injects itself into the same virtual machine as the app under test, giving TOLLER direct access to the app’s runtime memory. TOLLER is thus able to directly (1) access UI data structures, and thus capture contents on the screen without the overhead of invoking the Android framework services or remote procedure calls (RPCs), and (2) invoke UI event handlers without needing to execute the UI events. Compared with the often-used UIAutomator, TOLLER reduces average time usage of UI Hierarchy Capturing and UI Event Execution operations by up to 97% and 95%, respectively. We integrate TOLLER with existing state-of-the-art/practice Android UI testing tools and achieve the range of 11.8% to 70.1% relative code coverage improvement on average. We also find that TOLLER-enhanced tools are able to trigger 1.4x to 3.6x distinct crashes compared with their original versions without TOLLER enhancement. These improvements are so substantial that they also change the relative competitiveness of the tools under empirical comparison. Our findings highlight the practicality of TOLLER as well as raising the community awareness of infrastructure support’s significance beyond the community’s existing heavy focus on algorithms.« less
3. Vet: identifying and avoiding UI exploration tarpits

   https://doi.org/10.1145/3468264.3468554  

   Wang, Wenyu ; Yang, Wei ; Xu, Tianyin ; Xie, Tao ( August 2021 , In Proceedings of the 2021 ACM Joint European Software Engineering Conference and Symposium on the Foundations of Software Engineering (ESEC/FSE'21))

   Despite over a decade of research, it is still challenging for mobile UI testing tools to achieve satisfactory effectiveness, especially on industrial apps with rich features and large code bases. Our experiences suggest that existing mobile UI testing tools are prone to exploration tarpits, where the tools get stuck with a small fraction of app functionalities for an extensive amount of time. For example, a tool logs out an app at early stages without being able to log back in, and since then the tool gets stuck with exploring the app's pre-login functionalities (i.e., exploration tarpits) instead of its mainmore »functionalities. While tool vendors/users can manually hardcode rules for the tools to avoid specific exploration tarpits, these rules can hardly generalize, being fragile in face of diverted testing environments and fast app iterations. To identify and resolve exploration tarpits, we propose VET, a general approach including a supporting system for the given specific Android UI testing tool on the given specific app under test (AUT). VET runs the tool on the AUT for some time and records UI traces, based on which VET identifies exploration tarpits by recognizing their patterns in the UI traces. VET then pinpoints the actions (e.g., clicking logout) or the screens that lead to or exhibit exploration tarpits. In subsequent test runs, VET guides the testing tool to prevent or recover from exploration tarpits. From our evaluation with state-of-the-art Android UI testing tools on popular industrial apps, VET identifies exploration tarpits that cost up to 98.6% testing time budget. These exploration tarpits reveal not only limitations in UI exploration strategies but also defects in tool implementations. VET automatically addresses the identified exploration tarpits, enabling each evaluated tool to achieve higher code coverage and improve crash-triggering capabilities.« less
4. How well are regular expressions tested in the wild?

   https://doi.org/10.1145/3236024.3236072  

   Wang, Peipei ; Stolee, Kathryn T. ( January 2018 , Proceedings of the 2018 26th ACM Joint Meeting on European Software Engineering Conference and Symposium on the Foundations of Software Engineering)

   Developers report testing their regular expressions less than the rest of their code. In this work, we explore how thoroughly tested regular expressions are by examining open source projects. Using standard metrics of coverage, such as line and branch cov- erage, gives an incomplete picture of the test coverage of regular expressions. We adopt graph-based coverage metrics for the DFA representation of regular expressions, providing fine-grained test coverage metrics. Using over 15,000 tested regular expressions in 1,225 Java projects on GitHub, we measure node, edge, and edge-pair coverage. Our results show that only 17% of the regular expressions in themore »repositories are tested at all. For those that are tested, the median number of test inputs is two. For nearly 42% of the tested regular expressions, only one test input is used. Average node and edge coverage levels on the DFAs for tested regular expressions are 59% and 29%, respectively. Due to the lack of testing of regular expressions, we explore whether a string generation tool for reg- ular expressions, Rex, achieves high coverage levels. With some exceptions, we found that tools such as Rex can be used to write test inputs with similar coverage to the developer tests.« less
5. Do You Get What You Pay For? Comparing The Privacy Behaviors of Free vs. Paid Apps

   Han, Catherine ; Reyes, Irwin ; Elazari Bar On, Amit ; Reardon, Joel ; Feal, Álvaro ; Bamberger, Kenneth A. ; Egelman, Serge ; Vallina-Rodriguez, Narseo ( June 2019 , The Workshop on Technology and Consumer Protection (ConPro ’19))

   It is commonly assumed that the availability of “free” mobile apps comes at the cost of consumer privacy, and that paying for apps could offer consumers protection from behavioral advertising and long-term tracking. This work empirically evaluates the validity of this assumption by investigating the degree to which “free” apps and their paid premium versions differ in their bundled code, their declared permissions, and their data collection behaviors and privacy practices. We compare pairs of free and paid apps using a combination of static and dynamic analysis. We also examine the differences in the privacy policies within pairs. We relymore »on static analysis to determine the requested permissions and third-party SDKs in each app; we use dynamic analysis to detect sensitive data collected by remote services at the network traffic level; and we compare text versions of privacy policies to identify differences in the disclosure of data collection behaviors. In total, we analyzed 1,505 pairs of free Android apps and their paid counterparts, with free apps randomly drawn from the Google Play Store’s category-level top charts. Our results show that over our corpus of free and paid pairs, there is no clear evidence that paying for an app will guarantee protection from extensive data collection. Specifically, 48% of the paid versions reused all of the same third-party libraries as their free versions, while 56% of the paid versions inherited all of the free versions’ Android permissions to access sensitive device resources (when considering free apps that include at least one third-party library and request at least one Android permission). Additionally, our dynamic analysis reveals that 38% of the paid apps exhibit all of the same data collection and transmission behaviors as their free counterparts. Our exploration of privacy policies reveals that only 45% of the pairs provide a privacy policy of some sort, and less than 1% of the pairs overall have policies that differ between free and paid versions.« less