def METHOD_NAME(self):
    self.login_test1()
    d = self.create_doc(initial_par="Secret")
    p = d.document.get_last_par()
    self.assertEqual(p.get_markdown(), "Secret")
    res = self.post_preview(d, "", par=p.get_id())
    self.assertEqual(res["original_par"]["md"], "Secret")
    self.logout()
    res = self.post_preview(d, "", par=p.get_id())
    self.assertIsNone(res["original_par"])
    self.login_test2()
    res = self.post_preview(d, "", par=p.get_id())
    self.assertIsNone(res["original_par"])
    self.login_test1()
    self.test_user_2.grant_access(d, AccessType.edit)
    db.session.commit()
    self.login_test2()
    res = self.post_preview(d, "", par=p.get_id())
    self.assertEqual(res["original_par"]["md"], "Secret")