It is mostly a test of:
-How long users take to figure out to double-tap the screen (which IMHO is a better gesture, as it is less likely to be done accidentally than a swipe). On both platforms, users spent some time looking for a hardware button anyway ...
-How recognizable the icons for the 3 tested funcitons (with their size) are for first-time users. Inclusion of any more of the 21 functions on the default Harmattan app launcher screen would have changed the results significantly.

The 2nd test is skewed because the user seemed to be under the impression that their number was in the contacts on the phone (but this was not discounted ...).

In short, this is hardly a useful usability test at all. Of course, Nokia will probably take UI conventions/elements/icons to WP models anyway, so even if the tests were done well, they would be irrelevant regarding Nokia phones.