code: def test_reddit():
      # RedditDataset
      g = data.RedditDataset()[0]
      assert g.num_nodes() == 232965
      assert g.num_edges() == 114615892
      dst = F.asnumpy(g.edges()[1])
      assert np.array_equal(dst, np.sort(dst))
  
      transform = dgl.AddSelfLoop(allow_duplicate=True)
      g2 = data.RedditDataset(transform=transform)[0]
      assert g2.num_edges() - g.num_edges() == g.num_nodes()
  
imports: import gzip
  import io
  import os
  import tarfile
  import tempfile
  import unittest
  import backend
  import dgl
  import dgl.data
  import numpy
  import pandas
  import pytest
  import yaml
  from dgl import DGLError
label_desc: Use image node_id 1 for calling a global function with example usage: test_reddit() without return types