code: def test_forward(self):
      ts_head = TextSnakeHead(in_channels=10)
      data = torch.randn((2, 10, 40, 50))
      results = ts_head(data, None)
      self.assertEqual(results.shape, (2, 5, 40, 50))
  
imports: from unittest import TestCase
  import torch
  from mmocr.models.textdet.heads import TextSnakeHead
label_desc: Use image node_id 2 for calling the TestTextSnakeHead obj's underlying member method code with example usage: obj.test_forward() without return types