But first of all: how do you compare functional testing and non functional testing after all? Based on what criteria? Is the fail/pass threshold enough? At a first glance, it sure looks like there's nothing but the “non” —  functional vs non functional —  that differentiates the two software testing methodologies, right? Unlike other “pairs” of testing methods compared to one another: functional vs unit testing or functional testing vs integration testing... Are there actually 2 different sets of requirements? Can we be talking about 2 different sets of “checks”? …