'assuming that we know element N and we want to get element N-M
we should be able to get to element N-M without reading N-M elements
but by changing sorting and reading M elements'

@implementation
def test_feed_pagination(self):

    self.setup_ordering()
    page2 = self.test_feed[4:6]
    page3 = self.test_feed[7:9]
    page2_first_element = self.test_feed.filter(activity_id__gt=page3[0].serialization_id).order_by('activity_id')[:3][(-1)]
    self.assertEquals(page2[0], page2_first_element)
