With advanced computer technology, systems are getting larger to fulfill more complicated tasks, however, they are also becoming less reliable. Consequently, testing is an indispensable part of system design and implementation; yet it has proved to be a formidable task for complex systems. This motivates the study of testing finite state machines to ensure the correct functioning of systems and to discover aspects of their behavior. A finite state machine contains a finite number of states and produces outputs on state transitions after receiving inputs. Finite state machines are widely used to model systems in diverse areas, including sequential circuits, certain types of programs, and, more recently, communication protocols. In a testing problem we have a machine about which we lack some information; we would like to deduce this information by providing a sequence of inputs to the machine and observing the outputs produced. Because of its practical importance and theoretical intere...

Abstract. Researchers and practitioners are still trying to find effective ways to model and test Web applications. This paper proposes a system-level testing technique that combines test generation based on finite state machines with constraints. We use a hierarchical approach to model potentially large Web applications. The approach builds hierarchies of Finite State Machines (FSMs) that model subsystems of the Web applications, and then generates test requirements as subsequences of states in the FSMs. These subsequences are then combined and refined to form complete executable tests. The constraints are used to select a reduced set of inputs with the goal of reducing the state space explosion otherwise inherent in using FSMs. The paper illustrates the technique with a running example of a Web-based course student information system and introduces a prototype implementation to support the technique.

Here, the method proposed in [13] for constructing minimal-length checking sequences based on distinguishing sequences is improved. The improvement is based on optimizations of the state recognition sequences and their use in constructing test segments. It is shown that the proposed improvement further reduces the length of checking sequences produced from minimal, completely specified, and deterministic finite state machines. Index Terms---Finite state machine, checking sequence, test minimization, distinguishing sequence. # 1

Testing is a trade-off between increased confidence in the correctness of the implementation under test and constraints on the amount of time and effort that can be spent in testing. Therefore, the coverage, or adequacy of the test suite, becomes a very important issue. In this paper, we analyze basic ideas underlying the techniques for fault coverage analysis and assurance mainly developed in the context of protocol conformance testing based on finite state models. Special attention is paid to parameters which determine the testability of a given specification and influence the length of a test suite which guarantees complete fault coverage. We also point out certain issues which need further study. 1. INTRODUCTION Testing is a critical phase in the development life cycle for any hardware and software system, and in particular for communication systems for which it ensures the conformance to the relevant standards and compatibility or interoperability with other systems. Testing con...

In order to test the control portion of communication software, specifications are usually first abstracted to state machines, then test cases are generated from the resulting machines. The state machines obtained from the specification are often both partially-specified and nondeterministic. We come out with a method of generating test suites for the software that is modeled by partially-specified nondeterministic finite state machines (PNFSMs). On the basis of intuitive notions, a conformance relation, called quasi-equivalence, is introduced for such machines, which serves as a guide to test generation. Our method is also applicable to completely-specified deterministic machines, partially-specified deterministic machines, and completely-specified nondeterministic machines, which are typical classes of PNFSMs. When applied to such classes of machines, this method usually yields smaller test suites with full fault coverage for each class of machines than the existing methods for the ...

This paper describes a method for automatically generating unique input output (UIO) sequences for FSM conformance testing. UIOs are used in conformance testing to verify the end state of a transition sequence. UIO sequence generation is represented as a search problem and genetic algorithms are used to search this space. Empirical evidence indicates that the proposed method yields considerably better (up to 62 % better) results compared with random UIO sequence generation.

Abstract—This paper addresses the problem of test generation from partially specified deterministic Finite State Machines (FSMs) that may have indistinguishable states and, thus, are not necessarily reduced (minimized). The known methods for checking experiments that are based on state identification are not applicable to unreduced machines. We propose the so-called State-Counting approach that is directly applicable to unreduced FSMs. The approach generalizes the idea of state identification in test generation methods for deterministic machines.

Scenarios (Use cases) are used to describe the functionality and behavior of a (software) system in a user-centered perspective. As scenarios form a kind of abstract level test cases for the system under development, the idea to use them to derive test cases for system test is quite intriguing. Yet in practice scenarios from the analysis phase are seldom used to create concrete system test cases. In this paper we present a procedure to create scenarios in the analysis phase and use those scenarios in system test to systematically determine test cases. This is done by formalization of scenarios into statecharts, annotation of statecharts with helpful information for test case creation/generation and by path traversal in the statecharts to determine concrete test cases. KEYWORDS Scenario, use case, testing, scenario-based testing, statechart annotation 2 1

. Scenarios (Use cases) are a means to capture a system's functionality and behavior in a user-centered perspective. Thus they are used in most modern objectoriented software development methods to help elicit and document user requirements. Scenarios also form a kind of abstract level test cases for the system under development. Yet they are seldom used to derive concrete system test cases. In this paper we present a procedure to use scenarios in a defined way to systematically derive test cases for system test. This is done by formalization of natural language scenarios into statecharts, annotation of statecharts with helpful information for test case creation/generation and by path traversal in the statecharts to determine concrete test cases. 1. Introduction In developing a software system, validation and verification are recognized as vital activities. They are especially valuable when applied early in the development process, as errors found during the specification and...

A checking sequence, generated from a finite state machine, is a test sequence that is guaranteed to lead to a failure if the system under test is faulty and has no more states than the specification. The problem of generating a checking sequence for a finite state machine M is simplified if M has a distinguishing sequence: an input sequence ¯D with the property that the output sequence produced by M in response to ¯ D is different for the different states of M. Previous work has shown that, where a distinguishing sequence is known, an efficient checking sequence can be produced from the elements of a set A of sequences that verify the distinguishing sequence used and the elements of a set Υ of subsequences that test the individual transitions by following each transition t by the distinguishing sequence that verifies the final state of t. In this previous work A is a predefined set and Υ is defined in terms of A. The checking sequence is produced by connecting the elements of Υ and A, to form a single sequence, using a predefined acyclic set Ec of transitions. An optimization algorithm is used in order to produce the shortest such checking sequence that can be generated on the basis of the given A and Ec. However, this previous work did not state how the sets A and Ec should be chosen. This paper investigates the problem of finding appropriate A and Ec to be used in checking sequence generation. We show how a set A may be chosen so that it minimizes the sum of the lengths of the sequences to be combined. Further, we show that the optimization step, in the checking sequence generation algorithm, may be adapted so that it generates the optimal Ec. Experiments are used to evaluate the proposed method.