Negative Testing ..
I was asked to write negative testcases for a portion of requirement in a project. I was given Requirements Spec (reqns narrated in points), sample testcases and some screenshots. The application development is still going on. So right now there are some sample pieces of application and some screenshots. I would like to know is it possible to write negative testcases with screenshots and just if I have fair understanding about the workflow of module assigned to me or do I need to fetch more information to go ahead !
Re: Negative Testing ..
it is possible to create negative tests with this level of information and the use of some rules of thumb, heuristics, based on past experience of behaviours with similiar applications.
The workflow - or usecases if you have them, will give you a guide to how and where you may be able to force exceptions by doing something unexpected or different to the flow.
Screenshots, will hopefully supply you with ideas for which elements in the GUI could be abused by entering incorrect formats, long strings, unexpected characters or using tricks such as SQL injection.
There is an excellent paper on James Lyndsays website that has been presented at a number of conferences " A Positive View of Negative Testing " which can be downloaded as slides or a paper, also there is a recorded transcript of the talk there too on, http://www.workroom-productions.com/papers.html
For other attacks and ways of forcing errors on systems, including some tools to assist in this, the book: How to Break Software: A Practical Guide to Testing by James Whittaker is an excellent source of insperation and real value for money, IMHO.