Plone and Unit tests and ZSQL Methods

So, while writing running unit tests for a new class method, a call to a ZSQL method, in the skins folder, kept failing. Then after a long search, I finally found:

http://markmail.org/message/uhh3dhxvypfcnglu#query:plone%20skins%20%22unit%20test%22+page:1+mid:uhh3dhxvypfcnglu+state:results

So, the reason as stated is this:
because in tests new skin layers aren't automatically added to the
default search path on product installation.

So, adding this code to 'afterSetUp' solved everything for me:

def afterSetUp(self):
    self._refreshSkinData()