Lecture Notes in Computer Science 3472

448 Wolfgang Prenninger, Mohammad El-Ramly, and Marc Horstmann
Functional Structural Stochastic
specification specification specification
[BFdV + 99] Conference Protocol X
[CJRZ01] Smart Cards: CEPS X X
[DBG01] SDU of ST100 DSP X
[FHP02] POSIX/Java X X
[FKL99] PowerPC X X
[KVZ98] Cache Coherency Protocol X X
[PPS + 03] Smart Cards: WIM X X X
[SA99] Microprocessors X
Table 15.2. Test Specification Classes Used in the Reviewed Case Studies
number of possible test traces is reduced by defining additional functional constraints
concerning the system itself or its environment. Functional specifications
cover I/O relations which refer either to scenarios of specification documents as
described in Philipps et al. [PPS + 03] or other more special views that result
from experience, like fault intensive known sections as described in Fournier
et al. [FKL99]. In the majority of cases these requirements describe sequences
which can be completed to a state diagram, for example. The state diagram on
its own forms only one part of the specification, additional declarations about
the traces to be generated are necessary, for instance a restriction of the path
length. Otherwise, test cases of infinite size can be found. To overcome this
problem, often a functional specification is used in conjunction with structural
or stochastic test specifications. Functional specifications are used by three case
studies [FHP02, KVZ98, PPS + 03].
Structural Specification For the structural specifications, typical code coverage
criteria can be used which are lifted to the level of the test model. The spectrum
of coverage criteria varies from statement coverage [FKL99], state coverage
[DBG01], the MC/DC criterion [PPS + 03] up to path coverage [SA99] (for
an overview about existing coverage criteria cf. Sec. 11.3). Regardless of how
the test model is derived (SUT abstraction, manual modeling), the options of
which coverage criteria can be used depend on the complexity of the test model.
Those case studies where the resulting test model is already strongly tailored
to main test purposes, e.g. by an additional functional test specification or by
focusing on a special system part, use path coverage with a given trace length
[KVZ98]. Other studies using complex test models have to use more simple criteria
like state coverage [DBG01] or the MC/DC criterion [PPS + 03]. If structural
specification is used in combination with functional specification, then, it is important
that the structural criteria are applied to the model of the system and
the environment model with the defined constraints.
Stochastic Specification In Philipps et al. [PPS + 03] additional stochastic specifications
are applied to the result of structural specifications in order to reduce
the number of test cases. Belinfante et al. [BFdV + 99] use only this type of crite-