code: def testGetImageRepo(self):
      self.assertEqual(
          "tensorflow/tfx",
          builder._get_image_repo("tensorflow/tfx:latest"),
      )
      self.assertEqual(
          "tensorflow/tfx", builder._get_image_repo("tensorflow/tfx")
      )
      with self.assertRaises(ValueError):
          builder._get_image_repo("a/b:latest:wrong")
  
file_path: tfx/tfx/tools/cli/container_builder/builder_test.py
imports: from unittest import mock
  import docker
  import tensorflow
  from tfx.tools.cli.container_builder import builder
  from tfx.tools.cli.container_builder import dockerfile
label_desc: Use image node_id 1 for calling the BuilderTest obj's underlying member method code with example usage: obj.testGetImageRepo() without return types