Mao Zheng

Automated generation of test suites from formal specifications of real-time reactive systems

Real-time reactive systems are among the most difficult systems to test because of their size and complex time-dependent functionality. The number of test experiments for such systems is very large, if not infinite. Often such systems arise in safety-critical contexts. Hence, such systems require a rigorous analysis and thorough testing before they are deployed. This paper addresses test case generation methods and a metric-based test case selection algorithm for sufficient testing of real-time reactive systems. The methods are rigorous, and based on the formal specifications of the system and its fault models. The test generation and execution of algorithms are implemented in TROMLAB, a formal framework for developing real-time reactive systems. The methods are applied to the formal specification of the Train-Gate-Controller (TGC) example, a bench-mark case study in the real-time systems community. A brief description of the experimental results obtained on the case study is given.

Automated test generation from object-oriented specifications of real-time reactive systems

Real-time reactive systems are often safety-critical and hence must be thoroughly analyzed before they are deployed. We discuss methods for generating tests from object-oriented specifications of real-time reactive systems. Formal descriptions contain information on system entities, as mandated by requirements, as well as environmental entities, included in a domain model. These are exploited in the testing of an implementation, either for generating and sequencing tests, or as an oracle in evaluating test results. A tool has been developed based on the techniques and is being applied to several case studies developed in TROMLAB, a framework for a rigorous development of real-time reactive systems. The train-gate-controller (TGC) case study presented is one of them.

Specification-based testing for real-time reactive systems

We describe methods for specification based testing and testing measurement for real time reactive systems. The methods are based on an object oriented formal specification of real time reactive systems. Test cases generated by our method satisfy two test adequacy criteria, and minimally cover the global states and transitions of interest. The testing measurement provides measures of test suite adequacy in terms of coverage. We use a metric based algorithm to select the optimal set of test cases. One of the goals of this work is to automate these methods and integrate them into TROMLAB, a rigorous framework for the development of real time reactive systems.

A rigorous approach for constructing self-evolving real-time reactive systems

Abstract Self-evolving systems adapt themselves automatically to changing external situations and internal conditions. This paper proposes an architecture with four components, that, respectively, provides the infrastructure for formal architectural modeling of the evolving system, reuse of design elements, predicting the reliability of evolution, and managing change. The tools in TROMLAB, a framework for developing real-time reactive systems support and sustain the evolution of system components.

Managing complexity in real-time reactive systems

The paper discusses complexity categories associated with the phases of a process model that is followed in a rigorous development of real time reactive systems. We describe the complexity that is inherent in each phase and give measures to quantify it and methods to contain it. One of the goals of the work is to automate the measurement methods and integrate them into TROMLAB, a rigorous framework for the development of real time reactive systems.

Early quality monitoring in the development of real-time reactive systems

The increasing trend toward complex software systems has highlighted the need to incorporate quality requirements earlier in the development cycle. We propose a new methodology for monitoring quality in the earliest phases of real-time reactive system (RTRS) development. The targeted quality characteristics are functional complexity, performance, reliability, architectural complexity, maintainability, and test coverage. All these characteristics should be continuously monitored throughout the RTRS development cycle, to provide decision support and detect the first signs of low or decreasing quality as the system design evolves. The ultimate goal of this methodology is to assist developers in dealing with complex user requirements and ensure that the formal development process yields a high-quality application. Each aspect of quality monitoring is formalized mathematically and illustrated using a train-gate-controller case study.

Incremental testing for self-evolving timed systems

Self-evolving software systems in time-critical domains adapt themselves automatically to changes in external situations and internal conditions. This paper presents a black-box method for incrementally generating test cases for self-evolving systems.

A rigorous method for testing real-time reactive systems

Real-time reactive systems are complex systems to design and verify. Rigorous testing of real-time reactive systems complement the more difficult and expensive formal verification process. This paper discusses a rigorous method for block-box testing of real-time reactive systems, whose design specifications are given in the timed reactive object model (TROM) formalism.

A software architecture for multi-agent systems

Agent technology is widely used in the construction of large software systems, in particular E-Commerce and secure-critical systems. To fully utilize the potential of agents in the software system, it is essential to embed the BDI (Beliefs, Desires, Intentions) properties of agents in the software agents that model them. This paper introduces a formal software architectural design of a Multi-agent system (MAS) in which the BDI architecture is embedded. We embed the BDI properties of agents in an extended state machine (ESM) model and suggest that an implementation of the BDI architecture in a high-level programming language can be tested for conformance by generating test cases from the ESMs.

Reliability Analysis in the Early Development of Real-Time Reactive Systems

The increasing trend toward complex software systems has highlighted the need to incorporate quality requirements earlier in the development process. Reliability is one of the important quality indicators of such systems. This paper proposes a reliability analysis approach to measure reliability in the early development of real-time reactive systems (RTRS). The goal is to provide decision support and detect the first signs of low or decreasing reliability as the system design evolves. The analysis is conducted in a formal development environment for RTRS, formalized mathematically and illustrated using a train-gate-controller case study.