I'm confused, are we supposed to tell whether it matches any Major/Minor diatonic scale?

This sounds more like a melodic/scale test, not a pitch test, I was excepting it would ask something more like whether the instrument is well-tuned or whether a fretless instrument plays correctly.

For the curious, I've analyzed the first 5 songs with a program I'm developing, using the default C Major scale, here's the result : http://imgur.com/a/yx2H9 (I guess you could do it with something like Melodyne too).

EDIT: nevermind, this is just a cultural/memory test. You are supposed to know the tunes in advance and see if there is any « diff » with what you hear, melody-wise.

EDIT2: 21/26, I only knew more or less half of the songs, and knew well like a third. I Guess I have either poor culture or poor hear (or a little bit of both, we'll never know).