Information Technology Reference
In-Depth Information
4. Measure participant interaction during testing
5. Devise means for assessing usability
The categories Pressman provides for testing usability include: interactivity,
layout, readability, aesthetics, display characteristics, time sensitivity, personali-
zation, and accessibility. Some of these apply more directly to Web apps than
others.
10.5.7 System Integration
Systems may be designed from the top-down or bottom-up, however, regardless of
the approach chosen, components are created and may provide difficulty when
attempting to identify the source of errors as components are integrated into the
system. In order to reduce the difficulty that comes from integration of system
components, Sommerville points out that an incremental approach to system
integration and testing is beneficial (Sommerville
2004
). In this approach, you
integrate as few components as possible into the system and run sets of tests. Then,
components and test sets can be added to the minimal system and tested repeatedly
throughout this incremental process. Rather than testing the system will many or
all components, this approach will simplify testing and error location.
10.6 Mathematically Proving Correctness
A correctness proof is a mathematical technique for showing that a product is
correct, in other words, that it satisfies its specifications. The technique is some-
times termed verification. In addition, verification is also often used to denote all
non-execution based-techniques, not only correctness proving. For clarity, this
mathematical procedure will be termed correctness proving. A number of software
practitioners have put forward reasons why correctness proving should not be
viewed as a standard software engineering technique. First, it is claimed that
software engineers lack adequate mathematical training. Second, it is suggested
that proving is too expensive to be practical; third proving hard (Schach
2007
).
1. Nontrivial proofs require that input specifications, output specifications, and
loop invariance be expressed in first-or second-order predicate calculus or its
equivalent. Not only does this make the proof process simpler for a mathe-
matician, it allows correctness proving to be done by a computer. Fortunately,
most computer science majors today either take courses in the requisite material
or have the background to learn correctness-proving techniques on the job.
Therefore, colleges now are producing computer science graduates with suffi-
cient mathematical skills for correctness proving.
