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Leonardo Mariani

Publications and source records attributed to Leonardo Mariani.

At least 19 recordsLinked to original sources
arXiv2026

Generation of Web Apps with Agentic IDEs: An Empirical Assessment

Agentic IDEs are among the most significant innovations in software engineering, aiming to accelerate application development through LLM-based agents that can assist developers during development. However, their evaluation in end-to-end development tasks involving the generation of complete applications remains limited. To fill this gap, we propose a rigorous comparative analysis of three popular agentic IDEs (Copilot, Cursor, and Windsurf) in the generation of five full-stack Web applications from scratch. Results show high maturity in the generation of established patterns, such as CRUD operations and authentication features. In contrast, the generation of less common distributed architectures, such as a task queue architecture, produces significantly more errors. Overall, results show that Agentic IDEs cannot replace developers but shift their role toward building software by orchestrating LLM-based agents through natural-language instructions and iterative refinement. Yet, each agentic IDE shows its peculiarities, although differences are narrow.

cs.SE↗
arXiv2026

A Model-based Testing Technique for Amazon Lex Task-based Chatbots

Task-based chatbots are nowadays widely adopted software systems, usually integrated into real-world applications and communication channels, designed to assist users in completing tasks through conversational interfaces. Like any other software, even chatbots are prone to bugs. Despite their increasing pervasiveness in everyday activities, existing techniques for assessing their quality still exhibit several limitations, such as the simplicity of generated test scenarios and oracle weaknesses. In this paper, we present LexTester, an automated model-based testing technique for Amazon Lex chatbots. The technique explores the conversational space of the chatbot under test to generate a Dialog Graph of all possible interactions, from which an executable test suite is generated according to different coverage strategies. LexTester was evaluated against the state-of-the-practice chatbot testing tool Botium on five Amazon Lex chatbots, consistently outperforming it in all subjects, generating more tests with nearly double complexity, achieving overall 83-95% coverage of conversational elements, and improving fault detection effectiveness by up to four times at comparable time costs.

cs.SE↗
arXiv2026

GreenServ: Energy-Efficient Context-Aware Dynamic Routing for Multi-Model LLM Inference

Large language models (LLMs) demonstrate remarkable capabilities, but their broad deployment is limited by significant computational resource demands, particularly energy consumption during inference. Static, one-model-fits-all inference strategies are often inefficient, as they do not exploit the diverse range of available models or adapt to varying query requirements. This paper presents GreenServ, a dynamic, context-aware routing framework that optimizes the trade-off between inference accuracy and energy efficiency. GreenServ extracts lightweight contextual features from each query, including task type, semantic cluster, and text complexity, and routes queries to the most suitable model from a heterogeneous pool, based on observed accuracy and energy usage. We employ a multi-armed bandit approach to learn adaptive routing policies online. This approach operates under partial feedback, eliminates the need for extensive offline calibration, and streamlines the integration of new models into the inference pipeline. We evaluated GreenServ across five benchmark tasks and a pool of 16 contemporary open-access LLMs. Experimental results show that GreenServ consistently outperforms static (single-model) and random baselines. In particular, compared to random routing, GreenServ achieved a 22% increase in accuracy while reducing cumulative energy consumption by 31%. Finally, we evaluated GreenServ with RouterBench, achieving an average accuracy of 71.7% with a peak accuracy of 75.7%. All artifacts are open-source and available here: \href{https://github.com/TZData1/llm-inference-router}{GitHub}

cs.PF↗
arXiv2026

Automated Testing of Task-based Chatbots: How Far Are We?

Task-based chatbots are software, typically embedded in real-world applications, that assist users in completing tasks through a conversational interface. As chatbots are gaining popularity, effectively assessing their quality has become crucial. Whereas traditional testing techniques fail to systematically exercise the conversational space of chatbots, several approaches specifically targeting chatbots have emerged from both industry and research. Although these techniques have shown advancements over the years, they still exhibit limitations, such as simplicity of the generated test scenarios and weakness in implemented oracles. In this paper, we conduct a confirmatory study to investigate such limitations by evaluating the effectiveness of state-of-the-art chatbot testing techniques on a curated selection of task-based chatbots from GitHub, developed using the most popular commercial and open-source platforms.

cs.SE↗
arXiv2026

Assessing Task-based Chatbots: Snapshot and Curated Datasets for Dialogflow

In recent years, chatbots have gained widespread adoption thanks to their ability to assist users at any time and across diverse domains. However, the lack of large-scale curated datasets limits research on their quality and reliability. This paper presents TOFU-D, a snapshot of 1,788 Dialogflow chatbots from GitHub, and COD, a curated subset of TOFU-D including 185 validated chatbots. The two datasets capture a wide range of domains, languages, and implementation patterns, offering a sound basis for empirical studies on chatbot quality and security. A preliminary assessment using the Botium testing framework and the Bandit static analyzer revealed gaps in test coverage and frequent security vulnerabilities in several chatbots, highlighting the need for systematic, multi-Platform research on chatbot quality and security.

cs.SE↗
arXiv2026

"Where is My Troubleshooting Procedure?": Studying the Potential of RAG in Assisting Failure Resolution of Large Cyber-Physical System

In today's complex industrial environments, operators must often navigate through extensive technical manuals to identify troubleshooting procedures that may help react to some observed failure symptoms. These manuals, written in natural language, describe many steps in detail. Unfortunately, the number, magnitude, and articulation of these descriptions can significantly slow down and complicate the retrieval of the correct procedure during critical incidents. Interestingly, Retrieval Augmented Generation (RAG) enables the development of tools based on conversational interfaces that can assist operators in their retrieval tasks, improving their capability to respond to incidents. This paper presents the results of a set of experiments that derive from the analysis of the troubleshooting procedures available in Fincantieri, a large international company developing complex naval cyber-physical systems. Results show that RAG can assist operators in reacting promptly to failure symptoms, although specific measures have to be taken into consideration to cross-validate recommendations before actuating them.

cs.SE↗
arXiv2026

Coverage-Guided Road Selection and Prioritization for Efficient Testing in Autonomous Driving Systems

Autonomous Driving Assistance Systems (ADAS) rely on extensive testing to ensure safety and reliability, yet road scenario datasets often contain redundant cases that slow down the testing process without improving fault detection. To address this issue, we present a novel test prioritization framework that reduces redundancy while preserving geometric and behavioral diversity. Road scenarios are clustered based on geometric and dynamic features of the ADAS driving behavior, from which representative cases are selected to guarantee coverage. Roads are finally prioritized based on geometric complexity, driving difficulty, and historical failures, ensuring that the most critical and challenging tests are executed first. We evaluate our framework on the OPENCAT dataset and the Udacity self-driving car simulator using two ADAS models. On average, our approach achieves an 89% reduction in test suite size while retaining an average of 79% of failed road scenarios. The prioritization strategy improves early failure detection by up to 95x compared to random baselines.

cs.SE↗
arXiv2025

Experimental Limits on Planetary Mass Primordial Black Hole Mergers

The multi-mode acoustic gravitational wave experiment (MAGE) is a high-frequency gravitational wave detection experiment featuring cryogenic quartz bulk acoustic wave resonators operating as sensitive strain antennas in the MHz regime. After 61 days of non-continuous data collection, we present bounds on the observable merger rate density of primordial black hole binary systems of chirp mass $1.2\times10^{-4}M_\odot<\mathcal{M}<1.7\times10^{-9}M_\odot$. The maximum achieved limit on the merger rate density is $\mathcal{R}>1.3\times10^{18}~\mathrm{kpc}^{-3}\mathrm{yr}^{-1}$ which corresponds to constraining yearly mergers to a distance of reach on the order of the solar system, or $1.0\times10^{-6}$ kpc during the observational period. In addition, we exclude significantly rare and strong events similar to those observed in previous predecessor experiments as non-gravitational background signals, utilising coincident analysis between multiple detectors.

gr-qc↗
arXiv2025

E-Test: E'er-Improving Test Suites

Test suites are inherently imperfect, and testers can always enrich a suite with new test cases that improve its quality and, consequently, the reliability of the target software system. However, finding test cases that explore execution scenarios beyond the scope of an existing suite can be extremely challenging and labor-intensive, particularly when managing large test suites over extended periods. In this paper, we propose E-Test, an approach that reduces the gap between the execution space explored with a test suite and the executions experienced after testing by augmenting the test suite with test cases that explore execution scenarios that emerge in production. E-Test (i) identifies executions that have not yet been tested from large sets of scenarios, such as those monitored during intensive production usage, and (ii) generates new test cases that enhance the test suite. E-Test leverages Large Language Models (LLMs) to pinpoint scenarios that the current test suite does not adequately cover, and augments the suite with test cases that execute these scenarios. Our evaluation on a dataset of 1,975 scenarios, collected from highly-starred open-source Java projects already in production and Defects4J, demonstrates that E-Test retrieves not-yet-tested execution scenarios significantly better than state-of-the-art approaches. While existing regression testing and field testing approaches for this task achieve a maximum F1-score of 0.34, and vanilla LLMs achieve a maximum F1-score of 0.39, E-Test reaches 0.55. These results highlight the impact of E-Test in enhancing test suites by effectively targeting not-yet-tested execution scenarios and reducing manual effort required for maintaining test suites.

cs.SE↗
arXiv2025

Towards Multi-Platform Mutation Testing of Task-based Chatbots

Chatbots, also known as conversational agents, have become ubiquitous, offering services for a multitude of domains. Unlike general-purpose chatbots, task-based chatbots are software designed to prioritize the completion of tasks of the domain they handle (e.g., flight booking). Given the growing popularity of chatbots, testing techniques that can generate full conversations as test cases have emerged. Still, thoroughly testing all the possible conversational scenarios implemented by a task-based chatbot is challenging, resulting in incorrect behaviors that may remain unnoticed. To address this challenge, we proposed MUTABOT, a mutation testing approach for injecting faults in conversations and producing faulty chatbots that emulate defects that may affect the conversational aspects. In this paper, we present our extension of MUTABOT to multiple platforms (Dialogflow and Rasa), and present experiments that show how mutation testing can be used to reveal weaknesses in test suites generated by the Botium state-of-the-art test generator.

cs.SE↗
arXiv2025

Bug Whispering: Towards Audio Bug Reporting

Bug reporting is a key feature of mobile applications, as it enables developers to collect information about faults that escaped testing and thus affected end-users. This paper explores the idea of allowing end-users to immediately report the problems that they experience by recording and submitting audio messages. Audio recording is simple to implement and has the potential to increase the number of bug reports that development teams can gather, thus potentially improving the rate at which bugs are identified and fixed. However, audio bug reports exhibit specific characteristics that challenge existing techniques for reproducing bugs. This paper discusses these challenges based on a preliminary experiment, and motivates further research on the collection and analysis of audio-based bug reports

cs.SE↗
arXiv2025

Towards the Assessment of Task-based Chatbots: From the TOFU-R Snapshot to the BRASATO Curated Dataset

Task-based chatbots are increasingly being used to deliver real services, yet assessing their reliability, security, and robustness remains underexplored, also due to the lack of large-scale, high-quality datasets. The emerging automated quality assessment techniques targeting chatbots often rely on limited pools of subjects, such as custom-made toy examples, or outdated, no longer available, or scarcely popular agents, complicating the evaluation of such techniques. In this paper, we present two datasets and the tool support necessary to create and maintain these datasets. The first dataset is RASA TASK-BASED CHATBOTS FROM GITHUB (TOFU-R), which is a snapshot of the Rasa chatbots available on GitHub, representing the state of the practice in open-source chatbot development with Rasa. The second dataset is BOT RASA COLLECTION (BRASATO), a curated selection of the most relevant chatbots for dialogue complexity, functional complexity, and utility, whose goal is to ease reproducibility and facilitate research on chatbot reliability.

cs.SE↗
arXiv2025

From PREVENTion to REACTion: Enhancing Failure Resolution in Naval Systems

Complex and large industrial systems often misbehave, for instance, due to wear, misuse, or faults. To cope with these incidents, it is important to timely detect their occurrences, localize the sources of the problems, and implement the appropriate countermeasures. This paper reports our experience with a state-of-the-art failure prediction method, PREVENT, and its extension with a troubleshooting module, REACT, applied to naval systems developed by Fincantieri. Our results show how to integrate anomaly detection with troubleshooting procedures. We conclude by discussing a lesson learned, which may help deploy and extend these analyses to other industrial products.

cs.SE↗
arXiv2025

MultiMind: A Plug-in for the Implementation of Development Tasks Aided by AI Assistants

The integration of AI assistants into software development workflows is rapidly evolving, shifting from automation-assisted tasks to collaborative interactions between developers and AI. Large Language Models (LLMs) have demonstrated their effectiveness in several development activities, including code completion, test case generation, and documentation production. However, embedding AI-assisted tasks within Integrated Development Environments (IDEs) presents significant challenges. It requires designing mechanisms to invoke AI assistants at the appropriate time, coordinate interactions with multiple assistants, process the generated outputs, and present feedback in a way that seamlessly integrates with the development workflow. To address these issues, we introduce MultiMind, a Visual Studio Code plug-in that streamlines the creation of AI-assisted development tasks. MultiMind provides a modular and extensible framework, enabling developers to cost-effectively implement and experiment with new AI-powered interactions without the need for complex IDE customizations. MultiMind has been tested in two use cases: one for the automatic generation of code comments and the other about the definition of AI-powered chat.

cs.SE↗
arXiv2025

Test Case Generation for Dialogflow Task-Based Chatbots

Chatbots are software typically embedded in Web and Mobile applications designed to assist the user in a plethora of activities, from chit-chatting to task completion. They enable diverse forms of interactions, like text and voice commands. As any software, even chatbots are susceptible to bugs, and their pervasiveness in our lives, as well as the underlying technological advancements, call for tailored quality assurance techniques. However, test case generation techniques for conversational chatbots are still limited. In this paper, we present Chatbot Test Generator (CTG), an automated testing technique designed for task-based chatbots. We conducted an experiment comparing CTG with state-of-the-art BOTIUM and CHARM tools with seven chatbots, observing that the test cases generated by CTG outperformed the competitors, in terms of robustness and effectiveness.

cs.SE↗
arXiv2025

OpenCat: Improving Interoperability of ADS Testing

Testing Advanced Driving Assistance Systems (ADAS), such as lane-keeping functions, requires creating road topologies or using predefined benchmarks. However, the test cases in existing ADAS benchmarks are often designed in specific formats (e.g., OpenDRIVE) and tailored to specific ADAS models. This limits their reusability and interoperability with other simulators and models, making it challenging to assess ADAS functionalities independently of the platform-specific details used to create the test cases. This paper evaluates the interoperability of SensoDat, a benchmark developed for ADAS regression testing. We introduce OpenCat, a converter that transforms OpenDRIVE test cases into the Catmull-Rom spline format, which is widely supported by many current test generators. By applying OpenCat to the SensoDat dataset, we achieved high accuracy in converting test cases into reusable road scenarios. To validate the converted scenarios, we used them to evaluate a lane-keeping ADAS model using the Udacity simulator. Both the simulator and the ADAS model operate independently of the technologies underlying SensoDat, ensuring an unbiased evaluation of the original test cases. Our findings reveal that benchmarks built with specific ADAS models hinder their effective usage for regression testing. We conclude by offering insights and recommendations to enhance the reusability and transferability of ADAS benchmarks for more extensive applications.

cs.SE↗
arXiv2025

On the Possibility of Breaking Copyleft Licenses When Reusing Code Generated by ChatGPT

AI assistants can help developers by recommending code to be included in their implementations (e.g., suggesting the implementation of a method from its signature). Although useful, these recommendations may mirror copyleft code available in public repositories, exposing developers to the risk of reusing code that they are allowed to reuse only under certain constraints (e.g., a specific license for the derivative software). This paper presents a large-scale study about the frequency and magnitude of this phenomenon in ChatGPT. In particular, we generate more than 70,000 method implementations using a range of configurations and prompts, revealing that a larger context increases the likelihood of reproducing copyleft code, but higher temperature settings can mitigate this issue.

cs.SE↗