'Tests the update method of a List of Embedded Documents with
a single keyword.'

def test_single_keyword_update(self):

    number = self.post1.comments.update(author='user4')
    self.post1.save()
    comments = self.BlogPost.objects(id=self.post1.id)[0].comments
    self.assertEqual(comments[0].author, 'user4')
    self.assertEqual(comments[1].author, 'user4')
    self.assertEqual(number, 2)
