This has been bothering me for a while. Security, performance tests etc. are all done typically using the black box approach. But these are nonfunctional,while black box is called functional testing.
Is it because it judges the function and it is just a naming or there is an inconcistency?
Software Engineering by Salleh
Software Engineering and Testing by Gupta,Tayal
Software Engineering by A.A.Puntambekar
Software Testing : a Practical Approach by Sandeep Desai,Abhishek Srivastava
I cannot see the reason for downvote as obviously many are confused as I am (from the comments saying "I have never seen it before".