The pros and cons of using SDL for creation of distributed services

In a competitive market for the creation of complex distributed services, time to market, development cost, maintenance and flexibility are key issues. Optimizing the development process is very much a matter of optimizing the technologies used during service creation. This paper reports on the experience gained in the Service Creation projects SCREEN and TOSCA on use of the language SDL for efficient service creation

Creating telecommunication services based on object-oriented frameworks and SDL

This paper describes the tools and techniques being applied in the TINA Open Service Creation Architecture (TOSCA) project to develop object-oriented models of distributed telecommunication services in SDL. The paper also describes the way in which Tree and Tabular Combined Notation (TTCN) test cases are derived from these models and subsequently executed against the CORBA-based implementations of these services through a TTCN/CORBA gateway

Using formal methods to support testing

Formal methods and testing are two important approaches that assist in the development of high quality software. While traditionally these approaches have been seen as rivals, in recent years a new consensus has developed in which they are seen as complementary. This article reviews the state of the art regarding ways in which the presence of a formal specification can be used to assist testing

An Optimization of the TorX Test Generation Algorithm

In this paper we will discuss the process of automatic test derivation from formal specification. The process will be illustrated in the TORX algorithm. We will present an optimization of TORX. The extension of the algorithm with explicit probabilities leads to improvements in the tests generated with respect to the chances of finding errors in the implementation

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

Engineering telecommunication services with SDL

If formal techniques are to be more widely accepted then they should evolve as current software engineering approaches evolve. Current techniques in the development of distributed systems use interface definition languages (IDLs) as a basis for the underlying communication and also as an abstraction tool. Object-oriented technologies [6] and the idea of engineering software through frameworks [5] are also widely accepted approaches in developing software. In this paper we show how the formal specification language SDL and associated tool support have been applied in the TOSCA1 project to engineer telecommunication services using these current techniques

Standardized event pair based test generation method using TSS&TP

In the software engineering test development takes significant resources. A general method for the creation of appropriate test suites could solve the problems of the often ad-hoc and time-consuming test generation process. The recent method uses formal specifications to support systematic derivation of complete test suites. From the formal specification using a special procedure a formalized document, the so-called Test Suite Structure (TSS) and Test Purposes (TP) can be created. With the help of this document developers can easily, automatically implement the test suites. The TSS&TP document also enables the persons who perform the tests to understand the test criteria and the steps, even if they do not actually know the protocol itself. We present a thorough picture of our test derivation method and show its efficiency on the Wireless Transaction Protocol (WTP) of the Wireless Application Protocol family (WAP). During our work in the validation phase we also found some operational flaws in the protocol specification

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