'Fake C{os.fork}. Save the action in C{self.actions}, and return 0 if
C{self.child} is set, or a dumb number.'

def fork(self):

    self.actions.append(('fork', gc.isenabled()))
    if (self.raiseFork is not None):
        raise self.raiseFork
    elif self.child:
        return 0
    else:
        return 21
