Lecture Notes in Computer Science 3472

452 Wolfgang Prenninger, Mohammad El-Ramly, and Marc Horstmann
Finally, to generate a sequence of instructions, the test generation procedure
accepts the required number of instruction instances as input and activates the
instruction tree traversal. It also interleaves instruction generation with instruction
execution using the behavioral simulator. The intermediate processor state
is checked after the new instruction instance has been executed and a decision
is taken whether to include the new instance in the test or reject it. If the simulator
state after an executed instruction is undesirable, then it is rejected and
the state of the simulator is reverted.
15.7 Test Case Instantiation
Let us recall the following part of the model-based process described in Sec. 15.2:
A test model together with a test specification is used to generate one or more
test cases. Since the test model is an abstraction from the SUT the generated
test cases are abstract, too. In order to be able to execute the generated test
cases with the SUT they have to be instantiated. With this part of the process
in mind we describe the following aspects in this section:
• What is the motivation for the abstract test models and what abstraction
techniques are used in the literature? 1
• What limitations for testing are implied by these abstractions? 1
• What structures of test cases can be found in the literature?
• What methods are used to translate an abstract test case to a concrete one?
Note that the abstraction of the test model in respect to the SUT arises three
times in the model-based testing process: firstly, when building the abstract test
model, secondly, when bridging the abstraction gap between abstract test cases
and the SUT by instantiating the test cases, and finally, when evaluating the
test executions by comparing the abstracted system runs of the SUT with the
expected ones of the test model.
15.7.1 Abstractions in the Test Model
The purpose of the test models is: to support the validation process and the verification
process of the system under development. On the one hand the model is
used to formalize and to validate the system’s requirements. On the other hand
the model serves as specification and is used to test a system’s implementation
in order to verify the implementations behavior. Due to these requirements
the models abstract as far as possible from implementation details and concentrate
on the main aspects of the system. In this section we summarize briefly
the motivation for specifying abstract test models and we describe the different
abstraction techniques which are used in the reviewed literature.
1 the corresponding paragraph is partly taken from [PP04].