code: def test_set_dataset_root(self):
      orig_root = dataset.get_dataset_root()
      new_root = "/tmp/dataset_root"
      try:
          dataset.set_dataset_root(new_root)
          self.assertEqual(dataset.get_dataset_root(), new_root)
      finally:
          dataset.set_dataset_root(orig_root)
  
imports: import os
  import shutil
  import tempfile
  import unittest
  import mock
  from chainer import dataset
  from chainer import testing
label_desc: Use image node_id 1 for calling the TestGetSetDatasetRoot obj's underlying member method code with example usage: obj.test_set_dataset_root() without return types