Investigating Severity Thresholds for Test Smells

Test smells are poor design decisions implemented in test code, which can have an impact on the effectiveness and maintainability of unit tests. Even though test smell detection tools exist, how to rank the severity of the detected smells is an open research topic. In this work, we aim at investigating the severity rating for four test smells...

Does reviewer recommendation help developers?

Selecting reviewers for code changes is a critical step for an efficient code review process. Recent studies propose automated reviewer recommendation algorithms to support developers in this task. However, the evaluation of recommendation algorithms, when done apart from their target systems and users (i.e., code review tools and change...

Fine-grained just-in-time defect prediction

Defect prediction models focus on identifying defect-prone code elements, for example to allow practitioners to allocate testing resources on specific subsystems and to provide assistance during code reviews. While the research community has been highly active in proposing metrics and methods to predict defects on long-term periods (i.e.,at...

Test-Driven Code Review: An Empirical Study

Test-Driven Code Review (TDR) is a code review practice in which a reviewer inspects a patch by examining the changed test code before the changed production code. Although this practice has been mentioned positively by practitioners in informal literature and interviews, there is no systematic knowledge of its effects, prevalence, problems, and...

Information Needs in Contemporary Code Review

Contemporary code review is a widespread practice used by software engineers to maintain high software quality and share project knowledge. However, conducting proper code review takes time and developers often have limited time for review. In this paper, we aim at investigating the information that reviewers need<br/>to conduct a proper code...

A Graph-based Dataset of Commit History of Real-World Android apps

Obtaining a good dataset to conduct empirical studies on the engineering of Android apps is an open challenge. To start tackling this challenge, we present AndroidTimeMachine, the first, self-contained, publicly available dataset weaving spread-out data sources about real-world, open-source Android apps. Encoded as a graph-based database,...

PyDriller: Python Framework for Mining Software Repositories

Software repositories contain historical and valuable information about the overall development of software systems. Mining software repositories (MSR) is nowadays considered one of the most interesting growing fields within software engineering. MSR focuses on extracting and analyzing data available in software repositories to uncover...

Re-evaluating Method-Level Bug Prediction

Bug prediction is aimed at supporting developers in the identification of code artifacts more likely to be defective. Researchers have proposed prediction models to identify bug prone methods and provided promising evidence that it is possible to operate at this level of granularity. Particularly, models based on a mixture of product and process...

When Testing Meets Code Review: Why and How Developers Review Tests

Automated testing is considered an essential process for ensuring software quality. However, writing and maintaining high-quality test code is challenging and frequently considered of secondary importance. For production code, many open source and industrial software projects employ code review, a well-established software quality practice, but...

Mock objects for testing java systems: Why and how developers use them, and how they evolve

When testing software artifacts that have several dependencies, one has the possibility of either instantiating these dependencies or using mock objects to simulate the dependencies’ expected behavior. Even though recent quantitative studies showed that mock objects are widely used both in open source and proprietary projects, scientific...

Mining File Histories: Should we consider branches?

Modern distributed version control systems, such as Git, offer support for branching — the possibility to develop parts of software outside the master trunk. Consideration of the repository structure in Mining Software Repository (MSR) studies requires a thorough approach to mining, but there is no well-documented, widespread methodology...

Classifying Code Comments in Java Open-Source Software Systems

Code comments are a key software component containing information about the underlying implementation. Several studies have shown that code comments enhance the readability of the code. Nevertheless, not all the comments have the same goal and target audience. In this paper, we investigate how six diverse Java OSS projects use code comments,...

To Mock or Not To Mock?: An Empirical Study on Mocking Practices

When writing automated unit tests, developers often deal with software artifacts that have several dependencies. In these cases, one has the possibility of either instantiating the dependencies or using mock objects to simulate the dependencies' expected behavior. Even though recent quantitative studies showed that mock objects are widely used...

Visualizing code and coverage changes for code review

One of the tasks of reviewers is to verify that code modifications are well tested. However, current tools offer little support in understanding precisely how changes to the code relate to changes to the tests. In particular, it is hard to see whether (modified) test code covers the changed code. To mitigate this problem, we developed OPERIAS...

On the Reaction to Deprecation of 25,357 Clients of 4+1 Popular Java APIs

Application Programming Interfaces (APIs) are a tremendous resource—that is, when they are stable. Several studies have shown that this is unfortunately not the case. Of those, a large-scale study of API changes in the Pharo Smalltalk<br/>ecosystem documented several findings about API deprecations and their impact on API clients. We conduct a...

Social Diversity and Growth Levels of Open Source Software Projects on GitHub

Background: Projects of all sizes and impact are leveraging the services of the social coding platform GitHub to collaborate. Since users' information and actions are recorded, GitHub has been mined for over 6 years now to investigate aspects of the collaborative open source software (OSS) development paradigm. Aim: In this research, we use...

Work Practices and Challenges in Pull-Based Development: The Contributor’s Perspective

The pull-based development model is an emerging way of contributing to distributed software projects that is gaining enormous popularity within the open source software (OSS) world. Previous work has examined this model by focusing on projects and their owners-we complement it by examining the work practices of project contributors and the...

A security perspective on code review: The case of Chromium

Modern Code Review (MCR) is an established software development process that aims to improve software quality. Although evidence showed that higher levels of review coverage relates to less post-release bugs, it remains unknown the effectiveness of MCR at specifically finding security issues. We present a work we conduct aiming to fill that gap...