code: def test_encoder(self):
      encoder = ChannelReductionEncoder(512, 256)
      encoder.train()
      out_enc = encoder(self.feat, self.data_info)
      self.assertEqual(out_enc.shape, torch.Size([2, 256, 8, 25]))
  
imports: import unittest
  import torch
  from mmocr.models.textrecog.encoders import ChannelReductionEncoder
  from mmocr.structures import TextRecogDataSample
label_desc: Use image node_id 2 for calling the TestChannelReductionEncoder obj's underlying member method code with example usage: obj.test_encoder() without return types