'Test the _convert_date_time() method for seconds.'

def test_convert_date_time(self):

    for excel_date in self.excel_dates:
        date = datetime.datetime.strptime(excel_date[0], '%Y-%m-%dT%H:%M:%S.%f')
        got = self.worksheet._convert_date_time(date)
        exp = excel_date[1]
        self.assertAlmostEqual(got, exp, places=15)
