code: def test_ref(self):
      # Compare to _upsample2 and _downsample2
      for freq in [8, 16, 20, 28, 32, 36, 40, 56, 64]:
          x = pure_tone(freq, sr=128)
          y_gt_down = resample._downsample2(x)
          y_down = resample.resample_frac(x, 2, 1, rolloff=1)
          self.assertSimilar(y_down, y_gt_down, x, f"freq={freq} down")
          y_gt_up = resample._upsample2(x)
          y_up = resample.resample_frac(x, 1, 2, rolloff=1)
          self.assertSimilar(y_up, y_gt_up, x, f"freq={freq} up")
  
imports: import os
  import tempfile
  import uuid
  from pathlib import Path
  import math
  import random
  import unittest
  import resampy
  import torch
  from julius import resample, ResampleFrac
label_desc: Use image node_id 1 for calling the TestResampleFrac obj's underlying member method code with example usage: obj.test_ref() without return types