How to write unittests for events in a database or something hard to test for?

I have a process where I'm querying a database in chunks of 100000, and I want to retry up to 5 times if it is a timeout error, otherwise send out an alert. How could I write a unittest for this? I'm not exactly sure how to simulate the environment so I can double check the logic. It's also difficult to test the alert (it's an email), other than just sending it and seeing if it arrives. How would you write a test for this? Here is my code:

def _query_data(self, sql_query: str, retries: int = 5):
        cursor = self._return_cursor(self.canvas_conn)
        for attempt in range(retries):
            try:
                cursor.execute(sql_query)
            except (ppg2.ProgrammingError, ppg2.OperationalError) as e:
                if 'Operation timed out' in str(e):
                    print('Retrying, attempt {}'.format(attempt))
                    sleep(3)
                    continue
                elif self.historical_connect:
                    msg = 'Connected on last run, no longer available.'
                    self.set_for_alert(msg)
                    self.historical_connect = False
                raise ppg2.Error from e
            else:
                return self._iterate_results(cursor)

The error gets caught in the process that calls it.