def update(self, doc, process=None):
        if process is None:
            pk = 'id'
            id = doc.id
            doc.synced = False
            set = doc
        elif process == UPDATE_PROCESS:
            if self.db.docs.find({'sid': doc.sid}).count() == 0:
                return self.insert(doc, synced=True)
            pk = 'sid'
            id = doc.sid
            doc.synced = not doc.merged() # must be commited if was merged
            doc.merged(False)
            set = {'tid': doc.tid, 'data': doc.data, 'user': doc.user,
                   'public': doc.public, 'synced': doc.synced}
        elif process == COMMIT_PROCESS:
            pk = 'id'
            id = doc.id
            doc.synced = True
            set = {'sid': doc.sid, 'tid': doc.tid, 'synced': doc.synced}
        else:
            raise DatabaseException('Incorrect update process')

        try:
            rs = self.db.docs.update({pk: id}, {'$set': set}, safe=True)
            assert rs['n'] == 1
        except Exception as e:
            raise DatabaseException(e)
        return doc
def test_pre_update_validate_accepts_a_change_in_skill_difficulty_only(
            self):
        change = {
            'cmd': question_domain.CMD_CREATE_NEW_FULLY_SPECIFIED_QUESTION,
            'question_dict': {
                'question_state_data': self._create_valid_question_data(
                    'default_state').to_dict(),
                'language_code': 'en',
                'question_state_data_schema_version': (
                    feconf.CURRENT_STATE_SCHEMA_VERSION)
            },
            'skill_id': 'skill_1',
            'skill_difficulty': 0.3
        }

        suggestion = suggestion_registry.SuggestionAddQuestion(
            'exploration.exp1.thread1', 'exp1', 1,
            suggestion_models.STATUS_ACCEPTED, self.author_id,
            self.reviewer_id, change,
            'question.topic_1', 'en', self.fake_date)

        new_change = {
            'cmd': question_domain.CMD_CREATE_NEW_FULLY_SPECIFIED_QUESTION,
            'question_dict': {
                'question_state_data': self._create_valid_question_data(
                    'default_state').to_dict(),
                'language_code': 'en',
                'question_state_data_schema_version': (
                    feconf.CURRENT_STATE_SCHEMA_VERSION)
            },
            'skill_id': 'skill_1',
            'skill_difficulty': 0.6
        }

        self.assertEqual(
            suggestion.pre_update_validate(
                question_domain.QuestionSuggestionChange(new_change)), None)