code: def test_presto_get_fields(self):
      cols = [
          {"column_name": "column"},
          {"column_name": "column.nested_obj"},
          {"column_name": 'column."quoted.nested obj"'},
      ]
      actual_results = PrestoEngineSpec._get_fields(cols)
      expected_results = [
          {"column_name": '"column"', "label": "column"},
          {
              "column_name": '"column"."nested_obj"',
              "label": "column.nested_obj",
          },
          {
              "column_name": '"column"."quoted.nested obj"',
              "label": 'column."quoted.nested obj"',
          },
      ]
      for actual_result, expected_result in zip(
          actual_results, expected_results
      ):
          self.assertEqual(
              actual_result.element.name, expected_result["column_name"]
          )
          self.assertEqual(actual_result.name, expected_result["label"])
  
imports: from collections import namedtuple
  from textwrap import dedent
  from unittest import mock, skipUnless
  import pandas
  from flask.ctx import AppContext
  from sqlalchemy import types
  from sqlalchemy.sql import select
  from superset.db_engine_specs.presto import PrestoEngineSpec
  from superset.errors import ErrorLevel, SupersetError, SupersetErrorType
  from superset.sql_parse import ParsedQuery
  from superset.utils.database import get_example_database
  from tests.integration_tests.db_engine_specs.base_tests import TestDbEngineSpec
label_desc: Use image node_id 12 for calling the TestPrestoDbEngineSpec obj's underlying member method code with example usage: obj.test_presto_get_fields() without return types