code: def test_default_seed():
      """Test that the default seed is 0 when no seed provided and no environment variable set."""
      assert lightning.fabric.utilities.seed.seed_everything() == 0
      assert os.environ["PL_GLOBAL_SEED"] == "0"
  
file_path: pytorch-lightning/tests/tests_fabric/utilities/test_seed.py
imports: import os
  from unittest import mock
  from unittest.mock import Mock
  import lightning.fabric.utilities
  import pytest
  import torch
  from lightning.fabric.utilities.seed import _collect_rng_states, _set_rng_states
label_desc: Use image node_id 1 for calling a global function with example usage: test_default_seed() without return types