Lecture Notes in Computer Science 3472

12 Technology of Test-Case Generation
Levi Lúcio 1 and Marko Samer 2∗
1 Software Modelling and Verification Group
University of Geneva
levi.lucio@cui.unige.ch
2 Institute of Information Systems
Vienna University of Technology
samer@dbai.tuwien.ac.at
12.1 Introduction
Model based test case generation deals with the generation of test cases based
on test case specifications and a model of the system under test (SUT). Since the
number of possible test cases is in general too large to be practically useful, test
case specifications are used to select interesting test cases. Therefore, test case
generation can be seen as the search problem of finding appropriate test cases.
In the previous chapter, several kinds of test case specifications, in particular
coverage criteria, have been presented. In the current chapter, we will show how
techniques from various fields in computer science such as program analysis
and formal methods can be applied to generate test cases that satisfy such
specifications. The input part of each test case can then be fed into the SUT
whose output is compared with the output part of the test case in order to
detect errors. In particular, we will cover test case generation by theorem proving,
symbolic execution, andmodel checking. Although these techniques are often
used in combination, we will describe them separately in order to show their
applicability and specific features from different points of view.
Theorem proving can be used to support the generation of test cases from a
model that is given as formal specification. The basic assumption behind this
approach is that the model can be partitioned into equivalence classes which
represent the same behavior with respect to the test; in particular, test data
in the same equivalence class are assumed to cause the same error (or no error
in the case of success). Each such equivalence class represents one test case.
It is therefore sufficient to extract a small amount of test data from each test
case. We will present several approaches from the literature of how to find such
an appropriate partitioning of a given specification into equivalence classes. In
particular, we will show how general purpose theorem provers can be used to
transform Z specifications into test cases by syntactic transformations as well as
by taking semantic aspects into account. Moreover, we will show how Prolog can
∗
This author was supported by the European Community Research Training Network
“Games and Automata for Synthesis and Validation” (GAMES) and by the Austrian
Science Fund Project Z29-N04.
M. Broy et al. (Eds.): Model-Based Testing of Reactive Systems, LNCS 3472, pp. 323-354, 2005.
© Springer-Verlag Berlin Heidelberg 2005