SOFTWARE DESIGN VERIFICATION AND VALIDATION - Software Design for Six-Sigma: A Roadmap for Excellence - page 521

System engineering

S
R
D

Requirements
Design

Code

C

Unit test

U

I
V
ST

Integration test
Validation test
System test

FIGURE 19.13 Testing strategies during software cycle.

shows the testing strategies during a typical software cycle. The testing types that
will be conducted are as follows:

Unit testing
Integration testing
Validation testing
System testing

The development cycle deals with different kinds of V&V testing according to the
development phase.
At the very beginning and during the requirement phase, reviews and inspections
tests are used to assure the sufficiency of the requirements, the software correctness,
completeness, and consistency and must be analyzed carefully, and initial test cases
with the correct expected responses must be created.
During the design phase, validation tools should be developed, and test procedures
should be produced. Test data to exercise the functions introduced during the design
process as well as test cases should be generated based on the structure of the
application system. Simulation can be used here to verify specifications of the system
structures and subsystem interaction; also, a design walk-through can be used by the
developers to verify the flow and logical structure of the system. Furthermore, design
inspection and analysis should be performed by the test team to discover missing
cases, some logical errors/faults, faulty logic, I/O assumptions, and many other fault
issues to assure the software consistency.
Many test strategies are in the implementation phase applied. Static analysis is used
to detect errors by analyzing program characteristics. Dynamic analysis is performed
as the code actually executes, and it is used to determine test coverage through
various instrumentation techniques. Formal verification or proof techniques are used
on selected code to provide quality assurance.
At the deployment phase, and before delivering the software, maintenance costs
are expensive, especially if certain requirement changes are or a necessary certain