Conformance Testing with Labelled Transition Systems: Implementation Relations and Test Generation

This paper studies testing based on labelled transition systems, presenting two test generation algorithms with their corresponding implementation relations. The first algorithm assumes that implementations communicate with their environment via symmetric, synchronous interactions. It is based on the theory of testing equivalence and preorder, as is most of the testing theory for labelled transition systems, and it is found in the literature in some slightly different variations. The second algorithm is based on the assumption that implementations communicate with their environment via inputs and outputs. Such implementations are formalized by restricting the class of labelled transition systems to those systems that can always accept input actions. For these implementations a testing theory is developed, analogous to the theory of testing equivalence and preorder. It consists of implementation relations formalizing the notion of conformance of these implementations with respect to labelled transition system specifications, test cases and test suites, test execution, the notion of passing a test suite, and the test generation algorithm, which is proved to produce sound test suites for one of the implementation relations

Formally-Based Testing of Radiotherapy Accelerators

The paper presents the aims and research plan of the CONFORMED project (Conformance Of Radiological/Medical Devices). This three-year project will develop tools and techniques for modelling and testing radiotherapy equipment. Formal specifications in LOTOS (Language Of Temporal Ordering Specification) will be used to model accelerators formally and to derive tests rigorously based on these specifications

Analysis and representation of test cases generated from LOTOS

Cataloged from PDF version of article.This paper presents a method to generate, analyse and represent test cases from protocol specification. The language of temporal ordering specification (LOTOS) is mapped into an extended finite state machine (EFSM). Test cases are generated from EFSM. The generated test cases are modelled as a dependence graph. Predicate slices are used to identify infeasible test cases that must be eliminated. Redundant assignments and predicates in all the feasible test cases are removed by reducing the test case dependence graph. The reduced test case dependence graph is adapted for a local single-layer (LS) architecture. The reduced test cases for the LS architecture are enhanced to represent the tester's behaviour. The dynamic behaviour of the test cases is represented in the form of control graphs by inverting the events, assigning verdicts to the events in the enhanced dependence graph. © 1995

Protocol-Inspired Hardware Testing

The relevance of protocol conformance testing techniques to hardware testing is discussed. It is shown that the ioconf (input-output conformance) approach used in protocol testing can be applied to generate tests for a synchronous hardware design using its formal specification. The generated tests are automatically applied to a circuit by a VHDL testbench, thus giving confidence that the hardware design meets its high-level formal specification. Case studies illustrate how the ideas can be applied to standard hardware verification benchmarks such as the Single Pulser and Black-Jack Dealer

Testing real-time multi input-output systems

In formal testing, the assumption of input enabling is typically made. This assumption requires all inputs to be enabled anytime. In addition, the useful concept of quiescence is sometimes applied. Briefly, a system is in a quiescent state when it cannot produce outputs. In this paper, we relax the input enabling assumption, and allow some input sets to be enabled while others remain disabled. Moreover, we also relax the general bound M used in timed systems to detect quiescence, and allow different bounds for different sets of outputs. By considering the tioco-M theory, an enriched theory for timed testing with repetitive quiescence, and allowing the partition of input sets and output sets, we introduce the mtioco^M relation. A test derivation procedure which is nondeterministic and parameterized is further developed, and shown to be sound and complete wrt mtioco^

Formal description techniques for distributed computing systems:the challenges for the 1990's

Initially FDTs where developed within IS0 and CCITT for specification, at a high-level of abstraction, of distributed systems. Research is now being performed on the use of FDTs to support the complete implementation trajectory. In this paper we discuss a number of such research activities that are conducted within the framework of the Lotosphere project(*). The paper discusses aspects of design methodology, correctness preserving transformation, the reflection of design criteria, the role of pre-defined specification and implementation constructs, and formal approaches to conformance testing. Furthermore some insight is given in the development of a comprehensive toolset that supports these aspects of design methodology. The paper concludes with some experience obtained from the application of these methods and tools to some realistic pilot implementations: an ISDN and MHS application and a Transaction Processing application

Derivation of Test Cases for LAP-B from a LOTOS Specification

this paper, we show how this method has been applied to obtain test cases for LAP-B that are comparable, and in fact occasionally better, than those obtained by [KLPU][Kan]. Since TTCN is a common language for the spec- ification of test trees, the test cases obtained are written in TTCN (we should observe, however, that LOTOS itself appears to be adequate for the specification of test trees [Steen]). This technique appears to be valuable for conformance testing, at least until such time as the more formal approaches being developed by other authors become available (see Section 7). It makes it possible to extract test cases directly from (possibly standardized) formal descriptions, eliminating or reducing the importance of the interpretation of the informally specified standard. The formal specification is more complete and precise than the state tables and, unlike the latter, allows full formal treatment of the data part. For example, we shall show that automatic or semiautomatic generation of frame values appear to be possible by using the information contained in selection predicates