<< Chapter < Page
  Software engineering     Page 2 / 15
Chapter >> Page >

Regardless of the limitations, testing is an integral part in software development. It is broadly deployed in every phase in the software development cycle. Typically, more than 50% percent of the development time is spent in testing. Testing is usually performed for the following purposes:

To improve quality

As computers and software are used in critical applications, the outcome of a bug can be severe. Bugs can cause huge losses. Bugs in critical systems have caused airplane crashes, allowed space shuttle missions to go awry, halted trading on the stock market, and worse. Bugs can kill. Bugs can cause disasters. In a computerized embedded world, the quality and reliability of software is a matter of life and death.

Quality means the conformance to the specified design requirement. Being correct, the minimum requirement of quality, means performing as required under specified circumstances. Debugging, a narrow view of software testing, is performed heavily to find out design defects by the programmer. The imperfection of human nature makes it almost impossible to make a moderately complex program correct the first time. Finding the problems and get them fixed, is the purpose of debugging in programming phase.

For verification&Validation (v&V)

An important purpose of testing is verification and validation. Testing can serve as metrics. It is heavily used as a tool in the V&V process. Testers can make claims based on interpretations of the testing results, which either the product works under certain situations, or it does not work. We can also compare the quality among different products under the same specification, based on results from the same test.

We can not test quality directly, but we can test related factors to make quality visible. Quality has three sets of factors: functionality, engineering, and adaptability. These three sets of factors can be thought of as dimensions in the software quality space. Each dimension may be broken down into its component factors and considerations at successively lower levels of detail. Table 1 illustrates some of the most frequently cited quality considerations.

Functionality(exterior quality) Engineering(interior quality) Adaptability(future quality)
Correctness Efficiency Flexibility
Reliability Testability Reusability
Usability Documentation Maintainability
Integrity Structure
Table 1.  Typical Software Quality Factors 

Good testing provides measures for all relevant factors. The importance of any particular factor varies from application to application. Any system where human lives are at stake must place extreme emphasis on  reliability and integrity. In the typical business system usability and maintainability are the key factors, while for a one-time scientific program neither may be significant. Our testing, to be fully effective, must be geared to measuring each relevant factor and thus forcing quality to become tangible and visible.

Tests with the purpose of validating the product works are named clean tests, or positive tests. The drawbacks are that it can only validate that the software works for the specified test cases. A finite number of tests can not validate that the software works for all situations. On the contrary, only one failed test is sufficient enough to show that the software does not work. Dirty tests, or negative tests, refers to the tests aiming at breaking the software, or showing that it does not work. A piece of software must have sufficient exception handling capabilities to survive a significant level of dirty tests.

Questions & Answers

steps of developing a software
latest Reply
Present
win
which approach used to reduce number of test cases
Harshdeep Reply
I wish to ask what is the mean of a data model
Ateke Reply
explanation of working of computer
Gulfam Reply
hi
Moshiur
Hi
Malak
Hi
Yaw
How are you friends
Malak
Hlo nice too me
win
Thank for all fri
win
what's going on
Aden
lean for anything
win
hi guys
Ateke
hello.
Martins
hola como estas hey
Nurullohon
What is software engineering
parfait Reply
explain basic path testing for triangle problem?
Janavi Reply
Sorry
Mo
laptop ka meaning kaya hai
mahefuj Reply
hii bro
MOHD
hi
Aden
hi
Juhi
hi how are u doing bro
Aden
what you have?
Aden
Are you all Indians?
Bade
no I am ethiopian
Aden
I am a cameroonian
Ateke
please how can I design a game
Funmilayo Reply
manojsunani
Manoj
આ આ
Manoj
પોતાના
Manoj
JOHNBULL
EJE
how can supported ; learn me
win
what is software engineering
Darling Reply
software engineering are company manage
mahefuj
Text editor project in c++
Ayesha Reply
hi daddy
Sreenu
hello sir
Ranjith
are unmanned flying machines that are built and equipped with various kinds of software systems that allow them to see, hear, and act. Discuss some of the societal challenges of building such kinds of systems.
johni Reply
You have developed a prototype of a software system and your manager is very impressed by it. She proposes that it should be put into use as a production sys tem, with new features added as required. This avoids the expense of system dev immediately useful. Write a short report for your manager expl
johni
You have developed a prototype of a software system and your manager is very impressed by it. She proposes that it should be put into use as a production sys tem, with new features added as required. This avoids the expense of system dev immediately useful.
johni
You have developed a prototype of a software system and your manager is very impressed by it. She proposes that it should be put into use as a production sys tem, with new features added as required. This avoids the expense of system dev immediately useful.
johni
You have developed a prototype of a software system and your manager is very impressed by it. She proposes that it should be put into use as a production sys tem, with new features added as required. This avoids the expense of system dev immediately useful. Write a short report for your manager expl
johni
You have developed a prototype of a software system and your manager is very impressed by it. She proposes that it should be put into use as a production sys tem, with new features added as required. This avoids the expense of system dev immediately useful.
johni
what is cocomo ?
Surabhi Reply
?
StReeT
cocomo is cocote mo
Trixie
It means constructive cost model
Boris
HI
Masdul
hlo
Anuj
...
Moshiur
hello..
Moshiur
give me coding of these projects
Aman Reply
feasibility study&fact gathering techniques
Nachi Reply
write about software engineering
Mandala Reply
8.10.0.
BARBU

Get the best Software engineering course in your pocket!





Source:  OpenStax, Software engineering. OpenStax CNX. Jul 29, 2009 Download for free at http://cnx.org/content/col10790/1.1
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Software engineering' conversation and receive update notifications?

Ask