code: def test_init_with_valid_params(self):
      slack_api_post_operator = self.__construct_operator(
          SLACK_API_TEST_CONNECTION_ID, self.test_api_params
      )
      assert (
          slack_api_post_operator.slack_conn_id
          == SLACK_API_TEST_CONNECTION_ID
      )
      assert slack_api_post_operator.method == self.expected_method
      assert slack_api_post_operator.text == self.test_text
      assert slack_api_post_operator.channel == self.test_channel
      assert slack_api_post_operator.api_params == self.test_api_params
      assert slack_api_post_operator.username == self.test_username
      assert slack_api_post_operator.icon_url == self.test_icon_url
      assert (
          slack_api_post_operator.attachments == self.test_attachments
      )
      assert slack_api_post_operator.blocks == self.test_blocks
      assert not hasattr(slack_api_post_operator, "token")
  
imports: from __future__ import annotations
  import json
  from unittest import mock
  from unittest.mock import MagicMock
  import pytest
  from airflow.exceptions import AirflowProviderDeprecationWarning
  from airflow.providers.slack.operators.slack import SlackAPIFileOperator, SlackAPIOperator, SlackAPIPostOperator
label_desc: Use image node_id 3 for calling the TestSlackAPIPostOperator obj's underlying member method code with example usage: obj.test_init_with_valid_params() without return types