class_docstr: Test ArtifactExtractor class 
class_docstr_tok: ["Test","ArtifactExtractor","class"]
docstr: Setup before each method
docstr_tok: ["Setup","before","each","method"]
code: def setup(self):
      """Setup before each method"""
      with patch("boto3.client"):
          ArtifactExtractor._firehose_client = FirehoseClient(
              prefix="unit-test"
          )
  
      self._artifact_extractor = ArtifactExtractor(
          "unit_test_dst_fh_arn"
      )
  
file_path: streamalert/tests/unit/streamalert/shared/test_artifact_extractor.py
imports: from mock import call, patch
  from nose.tools import assert_equal
  from streamalert.shared.artifact_extractor import Artifact, ArtifactExtractor
  from streamalert.shared.firehose import FirehoseClient
  from tests.unit.streamalert.shared.test_utils import generate_artifacts, generate_categorized_records, MOCK_RECORD_ID
label_desc: Use image node_id 1 for calling the TestArtifactExtractor obj's underlying member method code with example usage: obj.setup() without return types