class_docstr: Test class for AthenaPartitioner when output data in Parquet format
docstr: Helper function for creating an sqs messsage body
docstr_tok: ["Helper","function","for","creating","an","sqs","messsage","body"]
code: def _create_test_message(count=2, placeholder=False):
      """Helper function for creating an sqs messsage body"""
      if placeholder:
          body = json.dumps(
              TestAthenaPartitioner._s3_record_placeholder_file()
          )
      else:
          count = min(count, 30)
          body = json.dumps(TestAthenaPartitioner._s3_record(count))
      return {
          "Records": [
              {
                  "body": body,
                  "messageId": "40d4fac0-64a1-4a20-8be4-893c51aebca1",
                  "attributes": {"SentTimestamp": "1534284301036"},
              }
          ]
      }
  
imports: import json
  import os
  from mock import Mock, patch, call
  from nose.tools import assert_equal, assert_true
  from streamalert.athena_partitioner.main import AthenaPartitioner
  from streamalert.shared.config import load_config
  from tests.unit.helpers.aws_mocks import MockAthenaClient
label_desc: Use image node_id 8 for calling the TestAthenaPartitioner obj's underlying member method code with example usage: obj._create_test_message(count, placeholder) and returns: dict