'Create this published hierarchy:
A
B1     B2
C1 C2  C3 C4'

def setUp(self):

    l = 'nav_playground.html'
    kw = dict(published=True, in_navigation=True)
    a = create_page('a', l, 'en', **kw)
    b1 = create_page('b1', l, 'en', parent=a, **kw)
    b2 = create_page('b2', l, 'en', parent=a, **kw)
    c1 = create_page('c1', l, 'en', parent=b1, **kw)
    c2 = create_page('c2', l, 'en', parent=b1, **kw)
    c3 = create_page('c3', l, 'en', parent=b2, **kw)
    c4 = create_page('c4', l, 'en', parent=b2, **kw)
    self.pages = [a, b1, c1, c2, b2, c3, c4]
    self.site = a.site
    self.user = self._create_user('standard', is_staff=False, is_superuser=False)
    self.other = self._create_user('other', is_staff=False, is_superuser=False)
    PagePermission.objects.create(page=b1, user=self.user, can_view=True, grant_on=ACCESS_PAGE_AND_DESCENDANTS)
    PagePermission.objects.create(page=b2, user=self.other, can_view=True, grant_on=ACCESS_PAGE_AND_DESCENDANTS)
    attrs = {'user': self.user, 'REQUEST': {}, 'POST': {}, 'GET': {}, 'session': {}}
    self.request = type('Request', (object,), attrs)
