docstr: Test that custom error messages are extracted correctly.
code: def test_extract_errors(self):
      """
      Test that custom error messages are extracted correctly.
      """
      msg = "mysql: Access denied for user 'test'@'testuser.com'"
      result = MySQLEngineSpec.extract_errors(Exception(msg))
      assert result == [
          SupersetError(
              error_type=SupersetErrorType.CONNECTION_ACCESS_DENIED_ERROR,
              message='Either the username "test" or the password is incorrect.',
              level=ErrorLevel.ERROR,
              extra={
                  "invalid": ["username", "password"],
                  "engine_name": "MySQL",
                  "issue_codes": [
                      {
                          "code": 1014,
                          "message": "Issue 1014 - Either the"
                          " username or the password is wrong.",
                      },
                      {
                          "code": 1015,
                          "message": "Issue 1015 - Either the database is "
                          "spelled incorrectly or does not exist.",
                      },
                  ],
              },
          )
      ]
  
      msg = "mysql: Unknown MySQL server host 'badhostname.com'"
      result = MySQLEngineSpec.extract_errors(Exception(msg))
      assert result == [
          SupersetError(
              error_type=SupersetErrorType.CONNECTION_INVALID_HOSTNAME_ERROR,
              message='Unknown MySQL server host "badhostname.com".',
              level=ErrorLevel.ERROR,
              extra={
                  "invalid": ["host"],
                  "engine_name": "MySQL",
                  "issue_codes": [
                      {
                          "code": 1007,
                          "message": "Issue 1007 - The hostname"
                          " provided can't be resolved.",
                      }
                  ],
              },
          )
      ]
  
      msg = (
          "mysql: Can't connect to MySQL server on 'badconnection.com'"
      )
      result = MySQLEngineSpec.extract_errors(Exception(msg))
      assert result == [
          SupersetError(
              error_type=SupersetErrorType.CONNECTION_HOST_DOWN_ERROR,
              message='The host "badconnection.com" might be '
              "down and can't be reached.",
              level=ErrorLevel.ERROR,
              extra={
                  "invalid": ["host", "port"],
                  "engine_name": "MySQL",
                  "issue_codes": [
                      {
                          "code": 1007,
                          "message": "Issue 1007 - The hostname provided"
                          " can't be resolved.",
                      }
                  ],
              },
          )
      ]
  
      msg = "mysql: Can't connect to MySQL server on '93.184.216.34'"
      result = MySQLEngineSpec.extract_errors(Exception(msg))
      assert result == [
          SupersetError(
              error_type=SupersetErrorType.CONNECTION_HOST_DOWN_ERROR,
              message='The host "93.184.216.34" might be down and can\'t be reached.',
              level=ErrorLevel.ERROR,
              extra={
                  "invalid": ["host", "port"],
                  "engine_name": "MySQL",
                  "issue_codes": [
                      {
                          "code": 10007,
                          "message": "Issue 1007 - The hostname provided "
                          "can't be resolved.",
                      }
                  ],
              },
          )
      ]
  
      msg = "mysql: Unknown database 'badDB'"
      result = MySQLEngineSpec.extract_errors(Exception(msg))
      assert result == [
          SupersetError(
              message='Unable to connect to database "badDB".',
              error_type=SupersetErrorType.CONNECTION_UNKNOWN_DATABASE_ERROR,
              level=ErrorLevel.ERROR,
              extra={
                  "invalid": ["database"],
                  "engine_name": "MySQL",
                  "issue_codes": [
                      {
                          "code": 1015,
                          "message": "Issue 1015 - Either the database is spelled incorrectly or does not exist.",
                      }
                  ],
              },
          )
      ]
  
      msg = "check the manual that corresponds to your MySQL server version for the right syntax to use near 'fromm"
      result = MySQLEngineSpec.extract_errors(Exception(msg))
      assert result == [
          SupersetError(
              message='Please check your query for syntax errors near "fromm". Then, try running your query again.',
              error_type=SupersetErrorType.SYNTAX_ERROR,
              level=ErrorLevel.ERROR,
              extra={
                  "engine_name": "MySQL",
                  "issue_codes": [
                      {
                          "code": 1030,
                          "message": "Issue 1030 - The query has a syntax error.",
                      }
                  ],
              },
          )
      ]
  
file_path: superset/tests/integration_tests/db_engine_specs/mysql_tests.py
imports: import unittest
  from sqlalchemy.dialects import mysql
  from sqlalchemy.dialects.mysql import DATE, NVARCHAR, TEXT, VARCHAR
  from superset.db_engine_specs.mysql import MySQLEngineSpec
  from superset.errors import ErrorLevel, SupersetError, SupersetErrorType
  from tests.integration_tests.db_engine_specs.base_tests import TestDbEngineSpec
label_desc: Use image node_id 4 for calling the TestMySQLEngineSpecsDbEngineSpec obj's underlying member method code with example usage: obj.test_extract_errors() without return types