Upon accepting Cythia's comments,
I can say both has its own weightage in completing testing to certifity the application/product is robust enough in identified practical possible conditions. However priority is always given to positive test cases as matter of fact all most all requirements come under positive cases. The negative cases are identified mostly by testing people.
Note: if you start with -ve testing then obviously you are encouraging developers to fix those bugs instead of focusing actual requirements implementation in which both management and customer are highly interested. At the same time if your application crashes/hangs then you will be answerable.
Take the example while application is running for test; First case only, if you either turn off power or remove hard disk connection or remove critical connection of inputs then raising a defects against these test cases means nothing but disturbing the development team. And hence positive cases are first priority.
Here is your view, My view inline with your's
Both are important, mainly its the time factor of the project & testing process in the company that decide you to take up the negative testing or not.
Do you know the difference between Process and Strategy??? it's strategy which decides not process. What about cost of the project???
Every stakeholder & decision makers of the project will be eagerly wanting to know all the postive scenario's have been passed first and if time permits they may ask the testing team to test the negative too.
They are eagerly awaiting for FUNCTIONING product not scenarios have been passed/failed. Your scenarios pass/fail doesn't matter to them when they encounter a critical issue. They don't have to ask testing team to test for negativity/positivity, it's TTs implicit job.
Yes i indeed know the difference.. but your process will follow the statergy which has been layed out.
So what do you mean a functioning product its nothing but your product which positive / negative scenarios passed. If the postive scenario of a product fails, you can never say the product is functioning...
Functioning product is FIT for use. Why are you so bothered about scenarios pass or fail? do you work to deliver a quality product or consider only pass/fail? There is nothing called positive or negative when your intention is to deliver a quality product. Don't live with age old ideas come out. In Modern Testing there is no room for scenarios, test cases, positive/negative.