code: def test_random_fps(device):
      N = 1024
      for _ in range(5):
          pos = torch.randn((2 * N, 3), device=device)
          batch_1 = torch.zeros(N, dtype=torch.long, device=device)
          batch_2 = torch.ones(N, dtype=torch.long, device=device)
          batch = torch.cat([batch_1, batch_2])
          idx = fps(pos, batch, ratio=0.5)
          assert idx.min() >= 0 and idx.max() < 2 * N
  
file_path: pytorch_cluster/test/test_fps.py
imports: from itertools import product
  import pytest
  import torch
  from torch import Tensor
  from torch_cluster import fps
  from torch_cluster.testing import devices, grad_dtypes, tensor
label_desc: Use image node_id 3 for calling a global function with example usage: test_random_fps(device) without return types