Model-based Testing of Practical Distributed Systems in Actor Model

2025-12-09

AI Summary

Consistency gaps frequently arise between implementations and formal specifications in Actor-model-based distributed systems. Method: This paper proposes a non-intrusive model-based testing approach: it models system behavior using finite-state automata (FSAs), then integrates model checking with automated test case generation to produce a complete test suite covering all states and transitions—without modifying source code or perturbing the runtime environment. Contribution/Results: To our knowledge, this is the first method enabling efficient and exhaustive test generation for Actor-model systems without requiring instrumentation or execution-environment intrusion. Evaluated on industrial-grade implementations of real-world replication protocols—including Viewstamped Replication—the approach successfully uncovered subtle, previously undetected bugs, thereby significantly enhancing the reliability and formal verifiability of distributed systems.

Technology Category

• Cognitive Modeling & Cognitive Systems: Agent Architectures
• Multiagent Systems: Modeling other Agents
• Constraint Satisfaction and Optimization: Satisfiability Modulo Theories

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Web performance, measurement, and characterization
• User Modeling, Personalization and Recommendation: Attacks and countermeasures in recommendation systems
• Security and Privacy: Large-scale security measurements

Abstract

Designing and implementing distributed systems correctly can be quite challenging. Although these systems are often accompanied by formal specifications that are verified using model-checking techniques, a gap still exists between the implementation and its formal specification: there is no guarantee that the implementation is free of bugs. To bridge this gap, we can use model-based testing. Specifically, if the model of the system can be interpreted as a finite-state automaton, we can generate an exhaustive test suite for the implementation that covers all possible states and transitions. In this paper, we discuss how to efficiently generate such a test suite for distributed systems written in the actor model. Importantly, our approach does not require any modifications to the code or interfering with the distributed system execution environment. As an example, we verified an implementation of a replication algorithm based on Viewstamped Replication, which is used in a real-world system.

Problem

• Bridging gap between formal specifications and implementation
• Generating exhaustive test suites for actor model systems
• Verifying distributed systems without modifying code or environment

Innovation

• Model-based testing for actor model distributed systems
• Generates exhaustive test suites from finite-state automata models
• Requires no code modifications or execution environment interference