code: def testResolveInputArtifacts(self):
      artifact_1 = standard_artifacts.String()
      artifact_1.id = 1
      channel_1 = types.Channel(
          type=standard_artifacts.String, producer_component_id="c1"
      ).set_artifacts([artifact_1])
      artifact_2 = standard_artifacts.String()
      artifact_2.id = 2
      channel_2 = types.Channel(
          type=standard_artifacts.String, producer_component_id="c2"
      ).set_artifacts([artifact_2])
      channel_3 = types.Channel(
          type=standard_artifacts.String, producer_component_id="c3"
      ).set_artifacts([standard_artifacts.String()])
      input_dict = {
          "input_union": channel.union([channel_1, channel_2]),
          "input_string": channel_3,
      }
      self._mock_metadata.search_artifacts.side_effect = [
          channel_3.get(),
          channel_1.get(),
          channel_2.get(),
      ]
  
      driver = base_driver.BaseDriver(
          metadata_handle=self._mock_metadata
      )
      resolved_artifacts = driver.resolve_input_artifacts(
          input_dict=input_dict,
          exec_properties=self._exec_properties,
          driver_args=self._driver_args,
          pipeline_info=self._pipeline_info,
      )
      self.assertLen(resolved_artifacts["input_union"], 2)
      self.assertEqual(
          resolved_artifacts["input_union"][0].value, _STRING_VALUE
      )
      self.assertLen(resolved_artifacts["input_string"], 1)
      self.assertEqual(
          resolved_artifacts["input_string"][0].value, _STRING_VALUE
      )
  
imports: import os
  from unittest import mock
  import tensorflow
  from tfx import types
  from tfx.dsl.components.base import base_driver
  from tfx.dsl.io import fileio
  from tfx.orchestration import data_types
  from tfx.types import channel
  from tfx.types import channel_utils
  from tfx.types import standard_artifacts
  from ml_metadata.proto import metadata_store_pb2
label_desc: Use image node_id 3 for calling the BaseDriverTest obj's underlying member method code with example usage: obj.testResolveInputArtifacts() without return types