code: def test_forward_good(self) -> None:
      pos_scores = torch.full((3,), +1e9, requires_grad=True)
      neg_scores = torch.full((3, 5), -1e9, requires_grad=True)
      loss_fn = SoftmaxLossFunction()
      loss = loss_fn(pos_scores, neg_scores, None)
      self.assertTensorEqual(loss, torch.zeros(()))
      loss.backward()
  
imports: from unittest import main, TestCase
  import torch
  from torchbiggraph.losses import LogisticLossFunction, RankingLossFunction, SoftmaxLossFunction
label_desc: Use image node_id 3 for calling the TestSoftmaxLossFunction obj's underlying member method code with example usage: obj.test_forward_good() without return types