docstr: When an artifact's uri points to a non-existent file, verify_artifacts fails.
docstr_tok: ["When","an","artifact","'s","uri","points","to","a","non-existent","file",",","verify_artifacts","fails","."]
code: def testVerifyArtifactsFailsMissingFile(self, mock_fileio):
      """When an artifact's uri points to a non-existent file, verify_artifacts fails."""
      artifact_instance = standard_artifacts.Examples()
      artifact_instance.uri = "/tmp/artifact"
      mock_fileio.exists.side_effect = lambda path: False
      with self.assertRaises(RuntimeError):
          artifact_utils.verify_artifacts(artifact_instance)
  
imports: import copy
  from unittest import mock
  from absl import logging
  import tensorflow
  from tfx.types import artifact
  from tfx.types import artifact_utils
  from tfx.types import standard_artifacts
  from tfx.types import system_artifacts
  from tfx.types import value_artifact
  from ml_metadata.proto import metadata_store_pb2
label_desc: Use image node_id 11 for calling the ArtifactUtilsTest obj's underlying member method code with example usage: obj.testVerifyArtifactsFailsMissingFile(mock_fileio) without return types