text: import pytest
  
  import numpy as np
  import pandas as pd
  
  from datashader.layout import circular_layout, forceatlas2_layout, random_layout
  
  
  @pytest.fixture
  def nodes():
      # Four nodes arranged at the corners of a 200x200 square with one node
      # at the center
      nodes_df = pd.DataFrame({'id': np.arange(5),
                               'x': [0., -100., 100., -100., 100.],
                               'y': [0., 100., 100., -100., -100.]})
      return nodes_df.set_index('id')
  
  
  @pytest.fixture
  def edges():
      # Four edges originating from the center node and connected to each
      # corner
      edges_df = pd.DataFrame({'id': np.arange(4),
                               'source': np.zeros(4, dtype=np.int64),
                               'target': np.arange(1, 5)})
      return edges_df.set_index('id')
  
  
  @pytest.mark.parametrize('layout', [random_layout, circular_layout, forceatlas2_layout])
  @pytest.mark.benchmark(group="layout")
  def test_layout(benchmark, nodes, edges, layout):
      benchmark(layout, nodes, edges)
  