code: def test_expand_var():
      with pytest.raises(ValueError, match="test_var is length 2"):
          tu.expand_var("test_var", (1, 2), 3, "reference_var")
  
imports: import collections
  import numpy
  import pytest
  import torch
  from torch import tensor
  import torch.nn.functional
  from garage.envs import GymEnv, normalize
  from garage.experiment.deterministic import set_seed
  from garage.torch import as_torch_dict, compute_advantages, flatten_to_single_vector, global_device, pad_to_last, product_of_gaussians, set_gpu_mode, state_dict_to, torch_to_np
  import garage.torch._functions
  from garage.torch.policies import DeterministicMLPPolicy
  from tests.fixtures import TfGraphTestCase
label_desc: Use image node_id 8 for calling a global function with example usage: test_expand_var() without return types