Scripted GUI Testing of Android Apps: A Study on Diffusion, Evolution and Fragility

Background. Evidence suggests that mobile applications are not thoroughly tested as their desktop counterparts. In particular GUI testing is generally limited. Like web-based applications, mobile apps suffer from GUI test fragility, i.e. GUI test classes failing due to minor modifications in the GUI, without the application functionalities being altered. Aims. The objective of our study is to examine the diffusion of GUI testing on Android, and the amount of changes required to keep test classes up to date, and in particular the changes due to GUI test fragility. We define metrics to characterize the modifications and evolution of test classes and test methods, and proxies to estimate fragility-induced changes. Method. To perform our experiments, we selected six widely used open-source tools for scripted GUI testing of mobile applications previously described in the literature. We have mined the repositories on GitHub that used those tools, and computed our set of metrics. Results. We found that none of the considered GUI testing frameworks achieved a major diffusion among the open-source Android projects available on GitHub. For projects with GUI tests, we found that test suites have to be modified often, specifically 5\%-10\% of developers' modified LOCs belong to tests, and that a relevant portion (60\% on average) of such modifications are induced by fragility. Conclusions. Fragility of GUI test classes constitute a relevant concern, possibly being an obstacle for developers to adopt automated scripted GUI tests. This first evaluation and measure of fragility of Android scripted GUI testing can constitute a benchmark for developers, and the basis for the definition of a taxonomy of fragility causes, and actionable guidelines to mitigate the issue.Comment: PROMISE'17 Conference, Best Paper Awar

Mobile GUI Testing Fragility: A Study on Open-Source Android Applications

Android applications do not seem to be tested as thoroughly as desktop ones. In particular, GUI testing appears generally limited. Like webbased applications, mobile apps suffer from GUI test fragility, i.e. GUI test classes failing or needing updates due to even minor modifications in the GUI or in the Application Under Test. The objective of our study is to estimate the adoption of GUI testing frameworks among Android opensource applications, the quantity of modifications needed to keep test classes up to date, and the amount of them due to GUI test fragility. We introduce a set of 21 metrics to measure the adoption of testing tools, the evolution of test classes and test methods, and to estimate the fragility of test suites. We computed our metrics for six GUI testing frameworks, none of which achieved a significant adoption among Android projects hosted on GitHub. When present, GUI test methods associated with the considered tools are modified often and a relevant portion (70% on average) of those modifications is induced by GUI-related fragilities. On average for the projects considered, more than 7% of the total modified lines of code between consecutive releases belong to test classes developed with the analysed testing frameworks. The measured percentage was higher on average than the one required by other generic test code, based on the JUnit testing framework. Fragility of GUI tests constitute a relevant concern, probably an obstacle for developers to adopt test automation. This first evaluation of the fragility of Android scripted GUI testing can constitute a benchmark for developers and testers leveraging the analysed test tools, and the basis for the definition of a taxonomy of fragility causes and guidelines to mitigate the issue

Evolution and Fragilities in Scripted GUI Testing of Android applications

In literature there is evidence that Android applications are not rigorously tested as their desktop counterparts. However – especially for what concerns the graphical User Interface of mobile apps – a thorough testing should be advisable for developers. Some peculiarities of Android applications discourage developers from performing automated testing. Among them, we recognize fragility, i.e. test classes failing because of modifications in the GUI only, without the application functionalities being modified. The aim of this study is to provide a preliminary characterization of the fragility issue for Android apps, dentifying some of its causes and estimating its frequency among Android open-source projects. We defined a set of metrics to quantify the amount of fragility of any testing suite, and measured them automatically for a set of repositories hosted on GitHub. We found that, for projects featuring GUI tests, the incidence of fragility is around 10% for test classes, and around 5% for test methods. This means that a significant effort has to be put by developers in fixing their test suites because of the occurrence of fragilities

Evolution and Fragility of Mobile Automated Test Suites

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Translation from Visual to Layout-based Android Test Cases: a Proof of Concept

Layout-based and Visual GUI testing are two approaches for testing mobile GUIs, both with individual benefits and drawbacks. Previous research has presented approaches to translate Layout-based scripts to hirdgen scripts but not the vice versa. The objective of this work is to provide Proof of Concept of the effectiveness of automatic translation between existing Visual test scripts to Layout-based test scripts. A tool architecture is presented and implemented in a tool capable of translating most hirdgen interactions with the GUI of an Android app into Layout-based instructions and oracles for the Espresso testing tool. We validate our approach on two test suites of our own creation, consisting of 30 test cases each. The measured success rate of the translation is 96.7% (58 working test cases out of 60 applications of the translator). The study provides support for the feasibility of a translation-based approach from Visual to Layout-based test cases. However, additional work is needed to make the approach applicable in real-world scenarios or larger open-source test suites

Towards Automated Translation between Generations of GUI-based Tests for Mobile Devices

Market demands for faster delivery and higher software quality are progressively becoming more stringent. A key hindrance for software companies to meet such demands is how to test the software due to to the intrinsic costs of development, maintenance and evolution of testware. Especially since testware should be defined, and aligned, with all layers of system under test (SUT), including all graphical user interface (GUI) abstraction levels. These levels can be tested with different generations of GUI-based test approaches, where 2nd generation, or Layout-based, tests leverage GUI properties and 3rd generation, or Visual, tests make use of image recognition. The two approaches provide different benefits and drawbacks and are seldom used together because of the aforementioned costs, despite growing academic evidence of the complementary benefits. In this work we propose the proof of concept of a novel two-step translation approach for Android GUI testing, where a translator first creates a technology independent script with actions and elements of the GUI, and then translates it to a script with the syntax chosen by the user. The approach enables users to translate Layout-based to Visual scripts and vice versa, to gain the benefits (e.g. robustness, speed and ability to emulate the user) of both generations, whilst minimizing the drawbacks (e.g. development and maintenance costs). We outline our approach from a technical perspective, discuss some of the key challenges with the realization of our approach, evaluate the feasibility and the advantages provided by our approach on an open-source Android application, and discuss the potential industrial impact of this work