Abstract

Abstract
In a growing number of domains, such as IoT for e-health and smart cities, the provisioning of end-to-end services to the users depends on the proper interoperation of multiple systems, forming a new distributed system, often subject to timing constraints. To ensure interoperability and integrity, it is important to conduct integration tests that verify the interactions with the environment and between the system components in key scenarios. To solve the test automation challenges, we propose algorithms for decentralized conformance checking and test input generation, and for checking and enforcing the conditions (local observability and controllability) that allow decentralized test execution. With this, we expect to improve the fault detection and localization capabilities and reduce the communication overhead comparatively to other model-based testing approaches. Our approach will be validated using real case studies from industrial partners.

Abstract
To ensure interoperability and the correct end-to-end behavior of heterogenous distributed systems, it is important to conduct integration tests that verify the interactions with the environment and between the system components in key scenarios. The automation of such integration tests requires that test components are also distributed, with local testers deployed close to the system components, coordinated by a central tester. In such a test architecture, it is important to maximize the autonomy of the local testers to minimize the communication overhead and maximize the fault detection capability. A test scenario is called locally observable and locally controllable, if conformance errors can be detected locally and test inputs can be decided locally, respectively, by the local testers, without the need for exchanging coordination messages between the test components during test execution (i.e., without any communication overhead). For test scenarios specified by means of UML sequence diagrams that don’t exhibit those properties, we present in this paper an approach with tool support to automatically find coordination messages that, added to the given scenario, make it locally controllable and locally observable. © Springer Nature Switzerland AG 2019.

Abstract
Internet-of-Things systems are comprised of highly heterogeneous architectures, where different protocols, application stacks, integration services, and orchestration engines co-exist. As they permeate our everyday lives, more of them become safety-critical, increasing the need for making them testable and fault-tolerant, with minimal human intervention. In this paper, we present a set of self-healing extensions for Node-RED, a popular visual programming solution for IoT systems. These extensions add runtime verification mechanisms and self-healing capabilities via new reusable nodes, some of them leveraging meta-programming techniques. With them, we were able to implement self-modification of flows, empowering the system with self-monitoring and self-testing capabilities, that search for malfunctions, and take subsequent actions towards the maintenance of health and recovery. We tested these mechanisms on a set of scenarios using a live physical setup that we called SmartLab. Our results indicate that this approach can improve a system’s reliability and dependability, both by being able to detect failing conditions, as well as reacting to them by self-modifying flows, or triggering countermeasures. © Springer Nature Switzerland AG 2020.

Abstract
Evermore end-to-end digital services depend on the proper interoperation of multiple products, forming a distributed system, often subject to timing requirements. To ensure interoperability and the timely behavior of such systems, it is important to conduct integration tests that verify the interactions with the environment and between the system components in key scenarios. The automation of such integration tests requires that test components are also distributed, with local testers deployed close to the system components, coordinated by a central tester. Test coordination in such a test architecture is a big challenge. To address it, in this article we propose an approach based on the pre-processing of the test scenarios. We first analyze the test scenarios in order to check if conformance errors can be detected locally (local observability) and test inputs can be decided locally (local controllability) by the local testers for the test scenario under consideration, without the need for exchanging coordination messages between the test components during test execution. If such properties do not hold, we next try to determine a minimum set of coordination messages or time constraints to be attached to the given test scenario to enforce those properties and effectively solve the test coordination problem with minimal overhead. The analysis and enforcement procedures were implemented in the DCO Analyzer tool for test scenarios described by means of UML sequence diagrams. Since many local observability and controllability problems may be caused by design flaws or incomplete specifications, and multiple ways may exist to enforce local observability and controllability, the tool was designed as a static analysis assistant to be used before test execution. DCO Analyzer was able to correctly identify local observability and controllability problems in real-world scenarios and help the users fix the detected problems.

Abstract