A recent discussion within the SQS Agile testing community considered an agile perspective on the V-Model – was it relevant to agile or a legacy of waterfall models. The following response struck me as a very clever way of viewing the underlying value of the V-Model, and is relevant whatever delivery model is employed. Both iterative and sequential structures have a challenge to find different types of defects and the V-Model remains a useful way of differentiating between the levels of testing and their purpose.

“I would think in terms of the seven dwarves. 

Each of them is a miner specializing in finding different types of gemstones but when they work on software mining for defects each one is best at finding different types of defect. 

Happy – looks for happy path functional defects (can the software do the absolute minimum)

Doc – looks for things that are not well and has a look in the places people try and ignore (can the software handle exceptions)

Sleepy – is really good when he first wakes up (can the software start in all modes, in all places with all data combinations and what happens if bits go to sleep and then come back again)

Bashful – he appears quiet but will do things that would embarrass you (looks for security problems)

Angry – he likes to blast things (applies huge loads to the software and waits for it to break)

Sneezy – what happens when things are not well (can the software cope with full file stores, losing memory,…)

Dopey – doesn’t see well and trips over things (Is the software usable by dopey?) 

I think the main problem with this is that there are probably 27 specialist types of miner that you need but may be 7 is a good start.”