Friday, December 28, 2007

v model to w model

V-Model:

The V-model promotes the idea that the dynamic test stages (on the right hand side of the model) use the documentation identified on the left hand side as baselines for testing. The V-Model further promotes the notion of early test preparation.

The V-Model of testing

Early test preparation finds faults in baselines and is an effective way of detecting faults early. This approach is fine in principle and the early test preparation approach is always effective. However, there are two problems with the V-Model as normally presented.


The V-Model with early test preparation

There is rarely a perfect, one-to-one relationship between the documents on the left hand side and the test activities on the right. For example, functional specifications don’t usually provide enough information for a system test. System tests must often take account of some aspects of the business requirements as well as physical design issues for example. System testing usually draws on several sources of requirements information to be thoroughly planned.

V-Model has little to say about static testing at all. The V-Model treats testing as a back-door activity on the right hand side of the model. There is no mention of the potentially greater value and effectiveness of static tests such as reviews, inspections, static code analysis and so on. This is a major omission and the V-Model does not support the broader view of testing as a constantly prominent activity throughout the development lifecycle.

W Model:


The W-Model of testing

Paul Herzlich introduced the W-Model approach in 1993. The W-Model attempts to address shortcomings in the V-Model. Rather than focus on specific dynamic test stages, as the V-Model does, the W-Model focuses on the development products themselves. Essentially, every development activity that produces a work product is shadowed by a test activity. The purpose of the test activity specifically is to determine whether the objectives of a development activity have been met and the deliverable meets its requirements. In its most generic form, the W-Model presents a standard development lifecycle with every development stage mirrored by a test activity. On the left hand side, typically, the deliverables of a development activity (for example, write requirements) is accompanied by a test activity test the requirements and so on. If your organization has a different set of development stages, then the W-Model is easily adjusted to your situation. The important thing is this: the W-Model of testing focuses specifically on the product risks of concern at the point where testing can be most effective.


The W-Model and static test techniques.

If we focus on the static test techniques, you can see that there is a wide range of techniques available for evaluating the products of the left hand side. Inspections, reviews, walkthroughs, static analysis, requirements animation as well as early test case preparation can all be used.



The W-Model and dynamic test techniques.

If we consider the dynamic test techniques you can see that there is also a wide range of techniques available for evaluating executable software and systems. The traditional unit, integration, system and acceptance tests can make use of the functional test design and measurement techniques as well as the non-functional test techniques that are all available for use to address specific test objectives.

The W-Model removes the rather artificial constraint of having the same number of dynamic test stages as development stages. If there are five development stages concerned with the definition, design and construction of code in your project, it might be sensible to have only three stages of dynamic testing only. Component, system and acceptance testing might fit your normal way of working. The test objectives for the whole project would be distributed across three stages, not five. There may be practical reasons for doing this and the decision is based on an evaluation of product risks and how best to address them. The W-Model does not enforce a project symmetry that does not (or cannot) exist in reality. The W-model does not impose any rule that later dynamic tests must be based on documents created in specific stages (although earlier documentation products are nearly always used as baselines for dynamic testing. In projects using these methods, requirements and designs might be documented in multiple models so system testing might be based on several of these models (spread over several documents).

We use the W-Model in test strategy as follows. Having identified the specific risks of concern, we specify the products that need to be tested; we then select test techniques (static reviews or dynamic test stages) to be used on those products to address the risks; we then schedule test activities as close as practicable to the development activity that generated the products to be tested.

77 comments:

Anonymous said...

gr8 atuff
thanks for sharing your knowledge
http://sof-engineering.blogspot.com

Anonymous said...

gr8 atuff
thanks for sharing your knowledge
http://sof-engineering.blogspot.com

Paul Gerrard said...

This article is a plagiarised version of text from Paul Gerrard and Neil Thompson's book, 'Risk-Based E-Business Testing', Pages 56-59. See http://riskbasedtesting.com

The full text is also available on the Gerrard Consulting website here: http://gerrardconsulting.com/?q=node/531 This is probably where the 'authors' obtained this content.

susannadixon said...

hi..
this is really informative..
nice blog..

Anonymous said...

Someone essentially lend a hand to make severely articles
I'd state. This is the very first time I frequented your website page and up to now? I surprised with the research you made to create this actual put up extraordinary. Excellent job!

Feel free to visit my site; steinzeit ernährung

Anonymous said...

buy tramadol online can buy tramadol online legally - tramadol ultram dosage

Anonymous said...

alprazolam medication buy xanax online prescription - can xanax overdose be fatal

Anonymous said...

generic xanax generic xanax good - xanax bars hangover

Anonymous said...

buy tramadol online what is better tramadol or ultram - tramadol dosage by weight

Anonymous said...

Pretty! This was an extremely wonderful post. Many thanks for supplying this info.


Also visit my website :: membership wordpress theme

Anonymous said...

This piece of writing presents clear idea designed for the new people of
blogging, that really how to do running a blog.


Here is my blog post glutenfreie rezepte

Anonymous said...

buy tramadol online tramadol hcl 50 mg tablet high - buy tramadol england

Anonymous said...

buy xanax online no rx xanax 1mg with alcohol - took 2mg xanax

Anonymous said...

buy tramadol online cheap tramadol online no prescription - tramadol dosage for people

Anonymous said...

buy tramadol online tramadol 50mg recreational - tramadol online no prescription usa

Anonymous said...

xanax online alprazolam 0.5 mg street price - one time use xanax drug test

Anonymous said...

generic xanax xanax side effects hair loss - buy xanax no prescription mexico

Anonymous said...

cheap tramadol no prescription tramadol get you high - tramadol addiction treatment home

Anonymous said...

xanax online xanax bars pictures - xanax effects 1 mg

Anonymous said...

carisoprodol 350 mg soma carisoprodol drug test - high off carisoprodol 350 mg

Anonymous said...

buy tramadol online buy cheap tramadol cod - tramadol ultram drug test

Anonymous said...

xanax online xanax overdose treatment - buy brand name xanax online

Anonymous said...

cheap tramadol online buy tramadol online australia - buy tramadol usa next day delivery

Anonymous said...

order xanax online xanax and alcohol heath ledger - xanax side effects gas

Anonymous said...

cheap xanax online buy upjohn xanax online - xanax is what drug classification

Anonymous said...

Hello! I understand this is somewhat off-topic however I had to ask.
Does building a well-established blog such as yours require a
massive amount work? I'm brand new to running a blog however I do write in my journal every day. I'd like to start a blog so I can easily share my own experience
and feelings online. Please let me know if you have any recommendations or tips for brand new aspiring blog owners.
Appreciate it!

Feel free to visit my web-site - Vermögensberater in Wiesbaden

Anonymous said...

buy carisoprodol soma 350 mg narcotic - generic carisoprodol 350 mg

Anonymous said...

xanax online what will 1mg xanax do - xanax withdrawal blurred vision

Anonymous said...

Valuable information. Fortunate me I found your web site unintentionally, and I am shocked why this coincidence didn't came about earlier! I bookmarked it.

my page ... Finanzberater in Mainz
my webpage - Vermögensberatung in Mainz

Anonymous said...

buy tramadol online buy tramadol buy cod - tramadol 50 mg kaps

Anonymous said...

I don't even understand how I ended up here, but I thought this submit was great. I don't
recognize who you might be but certainly you are going to
a famous blogger in the event you are not already. Cheers!


Also visit my blog post finanzbuchhaltung

Anonymous said...

cialis online buy cialis and viagra online - cialis how long before it works

Anonymous said...

cialis online generic cialis prices - cialis 2.5 mg daily use

Anonymous said...

buy cialis online ho comprato cialis online - cheap generic cialis online

Anonymous said...

I do not even know how I ended up here, but I thought this post was great.
I don't know who you are but definitely you're going to a famous blogger if you aren't already ;) Cheers!

my web site; studio

Anonymous said...

This paragraph is actually a fastidious
one it helps new web visitors, who are wishing for blogging.


Also visit my web page; abnehmen ohne diat
My page - internet marketing plan

Anonymous said...

hi!,I really like your writing very a lot! share we keep in
touch extra approximately your article on AOL? I require a
specialist in this space to unravel my problem. May be that's you! Looking forward to peer you.

Here is my web site; wordpress installieren

Anonymous said...

buy tramadol cheap 100mg tramadol - buy tramadol dogs usa

Anonymous said...

Excellent blog! Do you have any helpful hints for aspiring
writers? I'm planning to start my own site soon but I'm a little lost on everything.
Would you advise starting with a free platform like Wordpress or go for a paid option?
There are so many options out there that I'm totally confused .. Any ideas? Thanks a lot!

Feel free to visit my weblog - steinzeit diät frühstück

Anonymous said...

http://landvoicelearning.com/#62431 normal dosage tramadol humans - tramadol headache

Anonymous said...

buy tramadol ultram buy tramadol online usa cheap - buy tramadol overnight

Anonymous said...

buy tramadol cash on delivery tramadol 50 mg medication - tramadol 50 mg safe

Anonymous said...

buy tramadol overnight purchase tramadol online cheap - buy tramadol online australia no prescription

Anonymous said...

http://landvoicelearning.com/#21906 tramadol withdrawal for dogs - tramadol 200mg high

Anonymous said...

http://blog.dawn.com/dblog/buy/#side-effects tramadol hcl 50mg street value - order tramadol online overnight shipping

Anonymous said...

Woah! I'm really enjoying the template/theme of this site. It's simple,
yet effective. A lot of times it's difficult to get that "perfect balance" between superb usability and appearance. I must say you have done a very good job with this. Additionally, the blog loads super quick for me on Chrome. Superb Blog!

my blog post: paleo diät erfolge

Anonymous said...

Heya i'm for the first time here. I came across this board and I to find It truly useful & it helped me out a lot. I'm hoping to offer something again and aid others like you aided me.


My web site: low carb protein

Anonymous said...

buy tramadol tramadol overdose serotonin - tramadol 50 mg

Anonymous said...

I was able to find good advice from your content.


my weblog; detox diet
Also see my website > low carb backmischung

Anonymous said...

Wonderful blog! Do you have any helpful hints for aspiring writers?
I'm hoping to start my own website soon but I'm a little lost on everything.

Would you advise starting with a free platform like Wordpress or go for a paid option?
There are so many options out there that I'm totally confused .. Any tips? Kudos!

Also visit my web blog; produkte mit wenig kohlenhydrate

Anonymous said...

http://buytramadolonlinecool.com/#59473 tramadol hydrochloride 50 mg high - tramadol 50 mg over counter

Anonymous said...

Asking questions are genuinely fastidious thing if you are not understanding something totally,
however this article gives fastidious understanding even.


Review my web site welche lenkmatte passt zu mir
Also see my web page: aldi lenkdrachen 2011

Anonymous said...

hello!,I really like your writing very so much!

proportion we be in contact more about your article
on AOL? I need a specialist in this space to solve my
problem. May be that's you! Having a look ahead to see you.

Review my webpage: wordpress kontakt

Anonymous said...

Useful information. Lucky me I discovered your site by accident, and I'm shocked why this accident did not took place earlier! I bookmarked it.

Also visit my page :: lenkmatte oder lenkdrachen empfehlung

Anonymous said...

I do agree with all the concepts you have offered on your
post. They're very convincing and can certainly work. Still, the posts are too brief for novices. May just you please prolong them a bit from subsequent time? Thanks for the post.

Feel free to surf to my blog post - Finanzberatung in Wiesbaden

Anonymous said...

buy tramadol no rx tramadol hcl 50 mg uses - buy tramadol online reviews

Anonymous said...

tramadol online order tramadol online reviews - buy tramadol online illegal

Anonymous said...

http://buytramadolonlinecool.com/#50897 tramadol withdrawal bloating - order cheap tramadol online

Anonymous said...

http://landvoicelearning.com/#74967 tramadol 50 mg 100 caps - tramadol for dogs usa

Anonymous said...

buy tramadol cheap online dosage for tramadol for dogs - tramadol cod online pharmacy

Anonymous said...

buy ativan online ativan compared to xanax - lorazepam 1 mg compared xanax

Anonymous said...

http://reidmoody.com/#92465 ativan withdrawal signs - ativan drug overdose

Anonymous said...

buy tramadol online tramadol no prescription next day delivery - tramadol legal to buy online

Anonymous said...

buy xanax online xanax zoloft side effects - very cheap xanax

Anonymous said...

buy tramadol online buy tramadol online no prescription usa - tramadol high like

Anonymous said...

xanax price xanax dosage recreational erowid - xanax effects kidneys

Anonymous said...

buy tramadol online can you buy tramadol over the counter usa - tramadol 50 mg bivirkninger

Anonymous said...

buy tramadol online buy tramadol online paypal - tramadol online no prescription overnight

Anonymous said...

alprazolam 0.5mg xanax pictures - xanax test positive drug test

Anonymous said...

buy tramadol online high does tramadol make you - can tramadol overdose do you

Anonymous said...

buy tramadol online tramadol 50mg vs 100mg - buy tramadol online utah

Anonymous said...

buy xanax online xanax xr 1 mg tablet - xanax bars wikipedia

Anonymous said...

http://ranchodelastortugas.com/#72895 pictures of 1mg xanax - xanax overdose icd-9 code

Anonymous said...

http://bayshorechryslerjeep.com/#6828 percocet xanax high - cheap xanax bars

Anonymous said...

where to buy xanax online no prescription xanax withdrawal kidney pain - xanax in system

Anonymous said...

Your οwn write-up offers pгoѵen beneficіаl
tο me perѕonally. Ιt’s really eduсational and you're naturally very experienced in this field. You possess popped my personal eyes for you to varying thoughts about this subject along with intriguing and strong content material.
My web blog :: Valium Online

Anonymous said...

order tramadol online buy tramadol180 - buy tramadol overnight