docstr: Tests behavior when cluster has only one worker.
docstr_tok: ["Tests","behavior","when","cluster","has","only","one","worker","."]
code: def test_single_worker(self):
      """Tests behavior when cluster has only one worker."""
      cluster_config, save_dir = task.get_worker_behavior_info(
          "some/dir/"
      )
      self.assertEqual(save_dir, "some/dir/")
      self.assertEqual(cluster_config, "")
  
file_path: ddsp/ddsp/training/docker/task_test.py
imports: import os
  from unittest import mock
  from ddsp.training.docker import task
  import tensorflow.compat.v2
label_desc: Use image node_id 3 for calling the GetWorkerBehaviorInfoTest obj's underlying member method code with example usage: obj.test_single_worker() without return types