Lecture Notes in Computer Science 3472

16 TTCN-3
George Din
Fraunhofer Fokus – Institute for Open Communication Systems
din@fokus.fraunhofer.de
16.1 Introduction
This chapter presents TTCN-3, the Testing and Test Control Notation, which
is the most used technology in the protocol testing field. Many of the previous
chapters concern the problem of how to create tests for a system we want to
test. In this chapter we consider the problem of test execution. Test execution
comprises the following activities: test data is applied to a SUT, the behavior
of the SUT is monitored, and expected and actual behaviors are compared in
order to yield a verdict.
Before presenting details about test execution with TTCN-3 we consider it
is worth presenting shortly the evolution of TTCN-3. The creation of TTCN-3
was an incremental process starting from a version which was adequate only
for protocol testing and finishing with a standardized, full-featured language
applicable for many testing domains.
16.1.1 Evolution of TTCN-3
The design process of TTCN language is presented by ITU (International Organization
for Standardization) in [ITU02]. TTCN was first published in 1992,
as an ISO standard. Since then, TTCN language has been intensively used to
specify tests for different technologies like Global System for Mobile Communication
(GSM), Digital Enhanced Cordless Technologies (DECT), Inteligent
Network Application Protocol (INAP), Integrated Services Digital Network (N-
ISDN, B-ISDN). This first version of TTCN was not a proper language, but a
tabular notation. It was not possible to describe concurrent behaviors within
the test system, which was an impediment to apply TTCN to test in parallel
the different facets of the system under test. There were missing concepts like
packaging, encapsulation and there was also no support for manipulating external
data like ASN1 1 (Abstract Syntax Notation One). All these became possible
in the TTCN-2 (Tree and Tabular Combined Notation) version proposed
in ISO/IEC (International Organization for Standardization and International
Electrotechnical Commission) and in ITU-T (InternationalTelecommunications
Union-Telecommunications Standard Sector) in 1998.
Although the language was improved, TTCN-2 was rather associated with
conformance testing and was not suitable for various kinds of testing such as
1
ASN.1 is the language used by the Open System Interconnection (OSI) protocols for
describing abstract syntax.
M. Broy et al. (Eds.): Model-Based Testing of Reactive Systems, LNCS 3472, pp. 465-496, 2005.
© Springer-Verlag Berlin Heidelberg 2005