docstr: Request available GPU
docstr_tok: ["Request","available","GPU"]
code: def test_gpu_available(self, mock_available, mock_get_gpus):
      """Request available GPU"""
      mock_available.return_value = True
      mock_get_gpus.return_value = ["0"]
  
      self.parser.add_argument(
          "--num_gpus", help="number of gpus to use", type=int
      )
      tf_args = self.parser.parse_args(["--num_gpus", "1"])
  
      map_fn = TFSparkNode.run(
          self.default_fn,
          tf_args,
          self.cluster_meta,
          self.tensorboard,
          self.log_dir,
          self.queues,
          self.background,
      )
      map_fn([0])
      self.assertEqual(os.environ["CUDA_VISIBLE_DEVICES"], "0")
  
file_path: TensorFlowOnSpark/tests/test_TFSparkNode.py
imports: import argparse
  import os
  import random
  import unittest
  from tensorflowonspark import gpu_info, reservation, TFSparkNode
  from unittest.mock import patch
label_desc: Use image node_id 5 for calling the TFSparkNodeTest obj's underlying member method code with example usage: obj.test_gpu_available(mock_available, mock_get_gpus) without return types