code: def test_upsample(self):
      # For those freq, _downsample2 should be almost decimation
      for freq in [8, 16, 20, 28, 32]:
          x = pure_tone(freq, sr=64)
          y_gt = pure_tone(freq, sr=128)
          y = resample._upsample2(x)
          self.assertSimilar(y, y_gt, x, f"freq={freq}")
  
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 TestUpsample2 obj's underlying member method code with example usage: obj.test_upsample() without return types