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Good partitioning requires knowledge of the software structure. A good testing plan will not only contain black-box testing, but also white-box approaches, and combinations of the two.

White-box testing

Contrary to black-box testing, software is viewed as a white-box, or glass-box in white-box testing, as the structure and flow of the software under test are visible to the tester. Testing plans are made according to the details of the software implementation, such as programming language, logic, and styles. Test cases are derived from the program structure. White-box testing is also called glass-box testing, logic-driven testing or design-based testing.

There are many techniques available in white-box testing, because the problem of intractability is eased by specific knowledge and attention on the structure of the software under test. The intention of exhausting some aspect of the software is still strong in white-box testing, and some degree of exhaustion can be achieved, such as executing each line of code at least once (statement coverage), traverse every branch statements (branch coverage), or cover all the possible combinations of true and false condition predicates (Multiple condition coverage).

Control-flow testing, loop testing, and data-flow testing, all maps the corresponding flow structure of the software into a directed graph. Test cases are carefully selected based on the criterion that all the nodes or paths are covered or traversed at least once. By doing so we may discover unnecessary "dead" code - code that is of no use, or never get executed at all, which can not be discovered by functional testing.

In mutation testing, the original program code is perturbed and many mutated programs are created, each contains one fault. Each faulty version of the program is called a mutant. Test data are selected based on the effectiveness of failing the mutants. The more mutants a test case can kill, the better the test case is considered. The problem with mutation testing is that it is too computationally expensive to use. The boundary between black-box approach and white-box approach is not clear-cut. Many testing strategies mentioned above, may not be safely classified into black-box testing or white-box testing. It is also true for transaction-flow testing, syntax testing, finite-state testing, and many other testing strategies not discussed in this text. One reason is that all the above techniques will need some knowledge of the specification of the software under test. Another reason is that the idea of specification itself is broad - it may contain any requirement including the structure, programming language, and programming style as part of the specification content.

We may be reluctant to consider random testing as a testing technique. The test case selection is simple and straightforward: they are randomly chosen. Random testing is more cost effective for many programs. Some very subtle errors can be discovered with low cost. And it is also not inferior in coverage than other carefully designed testing techniques. One can also obtain reliability estimate using random testing results based on operational profiles. Effectively combining random testing with other testing techniques may yield more powerful and cost-effective testing strategies.

Questions & Answers

The following text is encoded in base 64. Ik5ldmVyIHRydXN0IGEgY29tcHV0ZXIgeW91IGNhbid0IHRocm93IG91dCBhIHdpbmRvdyIgLSBTdGV2ZSBXb3puaWFr Decode it, and paste the decoded text here
Julian Reply
what to do you mean
Vincent
What is the command to list the contents of a directory in Unix and Unix-like operating systems
George Reply
how can i make my own software free of cost
Faizan Reply
The name of the author of our software engineering book is Ian Sommerville.
Doha Reply
what is software
Sampson Reply
the set of intruction given to the computer to perform a task
Noor
I want to know about prototype model in software engineering
Malli Reply
Prototype Model is a replica model. In this we plan and build a rough application. Further we launch it for users and if they give their feedback or need any enhancement then we add-on requested features as per the system/user requirements.
KUMAR
between JavaScript and html,which is the best to master first?
Njuguna Reply
You have to master HTML first before you do javascript. Actually Html is not a programming language it is used to make a skeleton of a webpage
Alfayo
yaah it so good to start with HTML first
Abel
what is a software
Carren Reply
I am not proficient in any programming language though I am learning python currently, is it necessary to be proficient in programming language before one can undergo this course
Israel Reply
what is software
Arwaz Reply
The reason it all exists
Ruth Reply
Hi
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Ajay
Hii
Biddika
hu
Ajay
what is programming
Nonny Reply
software project scheduling
DEVENDRA Reply
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shiv
Green chili
Arwaz
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my
what is soft ware
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Hilal
how to communicate with clients
adejoh Reply
hey hi good afternoon sir my name is Mohamed Kamara, I want to understand how to do it sir.
Muhammadosman
ok
Ronald
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Muhammadosman
me too I need this knowledge
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me too
Noor
what's up y'all..who is good at java? need help
Adrian
Is it like a unit in software engineering or what?
Njuguna
Which SDLC Model will you select to develop the system as a software engineer and why?
Subrato Reply

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Source:  OpenStax, Software engineering. OpenStax CNX. Jul 29, 2009 Download for free at http://cnx.org/content/col10790/1.1
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