code: def test_disk_usage(self):
      path = pjoin(self.tmp_path, "disk-usage-base")
      p1 = pjoin(path, "p1")
      p2 = pjoin(path, "p2")
  
      subdir = pjoin(path, "subdir")
      p3 = pjoin(subdir, "p3")
  
      if self.hdfs.exists(path):
          self.hdfs.delete(path, True)
  
      self.hdfs.mkdir(path)
      self.hdfs.mkdir(subdir)
  
      data = b"foobarbaz"
  
      for file_path in [p1, p2, p3]:
          with self.hdfs.open(file_path, "wb") as f:
              f.write(data)
  
      assert self.hdfs.disk_usage(path) == len(data) * 3
  
imports: import os
  import random
  from io import BytesIO
  from os.path import join
  import numpy
  import pytest
  import pyarrow
  from pyarrow.tests import util
  from pyarrow.tests.parquet.common import _test_dataframe
  from pyarrow.tests.parquet.test_dataset import _test_write_to_dataset_with_partitions, _test_write_to_dataset_no_partitions
  from pyarrow.util import guid
label_desc: Use image node_id 12 for calling the HdfsTestCases obj's underlying member method code with example usage: obj.test_disk_usage() without return types