code: def test_metadata(self):
      pb = self.histogram("h", [], description="foo")
      self.assertEqual(len(pb.value), 1)
      summary_metadata = pb.value[0].metadata
      self.assertEqual(summary_metadata.summary_description, "foo")
      plugin_data = summary_metadata.plugin_data
      self.assertEqual(plugin_data.plugin_name, metadata.PLUGIN_NAME)
      parsed = metadata.parse_plugin_metadata(plugin_data.content)
      self.assertEqual(metadata.PROTO_VERSION, parsed.version)
  
imports: import glob
  import os
  import numpy
  import tensorflow
  from tensorboard.compat import tf2
  from tensorboard.compat.proto import summary_pb2
  from tensorboard.plugins.histogram import metadata
  from tensorboard.plugins.histogram import summary
  from tensorboard.util import tensor_util
label_desc: Use image node_id 3 for calling the SummaryBaseTest obj's underlying member method code with example usage: obj.test_metadata() without return types