Information Technology Reference
In-Depth Information
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o
0
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Add
Unit Delay
Saturation [1,5]
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Subtract
Division
1
Constant
Fig. 1.
A Simulink model example
Currently, our Simulink front-end supports a set of commonly used block types
that belong to a variety of Simulink libraries, such as
Math, Discrete, Logic and
Bit, Sinks, Sources, Ports&Subsystems, Discontinuities, Signal Routing, Signal
Attributes
and
Model Verification
. Some important block types include
Subsys-
tems
,
Unit Delay
that forms feedback loops,
Switches
,and
From/Goto
pairs.
With our uniform definition artifacts, further block types can easily be added to
the library as needed. Support for Stateflow diagrams is under development.
The transformation source is a Simulink model composed of a set of intercon-
nected blocks, organized into a hierarchy of subsystems. The front-end parses the
model, flattens the hierarchy and derives an appropriate block execution order
which determines the simulation order of blocks in the resulting ANSI-C model.
The front-end identifies the type and property specifications of each individual
block instance and maps it to the corresponding block-type definition in the li-
brary. Then, it determines which C block-type definitions need to be included and
assigns values to block properties. Some analyses like type inference are also per-
formed during the transformation to resolve ambiguities in the Simulink model.
Figure 2 shows the basic structure of the C code transformed from the model
in Figure 1 with the front-end. Our analysis and test-case generation approach
based on the resulting C code is introduced in the sections below.
3 Generating Test Cases Using Mutations
3.1
Overview
Many existing test case generation techniques permit the generation of test suites
that satisfy structural coverage criteria such as condition or statement coverage.
One approach to achieve such coverage is to use a
model checker
, which can gen-
erate counterexamples that demonstrate the reachability of certain statements
or conditions.
