Prepared publications

Those papers are under review and will continue evolving in the future, any feedback will be greatly appreciated

A Comprehensive Study of Pseudo-tested Methods

Pseudo-tested methods are defined as follows: they are covered by the test suite, yet no test case fails when the method body is removed, i.e., when all the effects of this method are suppressed. This intriguing concept was coined in 2016, by Niedermayr and colleagues, who showed that such methods are systematically present, even in well-tested projects with high statement coverage.
This work presents a novel analysis of pseudo-tested methods. First, we run a replication of Niedermayr’s study, enhancing its external validity thanks to the use of new tools and new study subjects. Second, we perform a systematic characterization of these methods, both quantitatively and qualitatively with an extensive manual analysis.
The first part of the study confirms Niedermayr’s results: pseudo-tested methods exist in all our subjects. Our in-depth characterization of pseudo-tested leads to two key insights: pseudo-tested methods are significantly less tested than the other methods; yet, for most of them, the developers would not pay the testing price to fix this situation. This calls for future work on targeted test generation to specify those pseudo-tested methods without spending developer time.

The Emerging Field of Test Amplification: A Survey

The adoption of agile development approaches has put an increased emphasis on developer testing, resulting in software projects with strong test suites. These suites include a large number of test cases, in which developers embed knowledge about meaningful input data and expected properties in the form of oracles.
This article surveys various works that aim at exploiting this knowledge in order to enhance these manually written tests with respect to an engineering goal (e.g., improve coverage of changes or increase the accuracy of fault localization). While these works rely on various techniques and address various goals, we believe they form an emerging and coherent field of research, which we call “test amplification”.
We devised a first set of papers from DBLP, looking for all papers containing “test” and “amplification” in their title. We reviewed the 70 papers in this set and selected the 4 papers that fit our definition of test amplification. We use these 4 papers as the seed for our snowballing study, and systematically followed the citation graph.
This study is the first that draws a comprehensive picture of the different engineering goals proposed in the literature for test amplification. In particular, we note that the goal of test amplification goes far beyond maximizing coverage only.
We believe that this survey will help researchers and practitioners entering this new field to understand more quickly and more deeply the intuitions, concepts and techniques used for test amplification.

A Chaos Engineering System for Live Analysis and Falsification of Exception-handling in the JVM

Software systems contain resilience code to handle those failures and unexpected events happening in production. It is essential for developers to understand and assess the resilience of their systems. Chaos engineering is a technology that aims at assessing resilience and uncovering weaknesses by actively injecting perturbations in production. In this paper, we propose a novel design and implementation of a chaos engineering system in Java called CHAOSMACHINE. It provides a unique and actionable analysis on exception-handling capabilities in production, at the level of try-catch blocks. To evaluate our approach, we have deployed CHAOSMACHINE on top of 3 large-scale and well-known Java applications totaling 630k lines of code. Our results show that CHAOSMACHINE reveals both strengths and weaknesses of the resilience code of a software system at the level of exception handling.