text: import os
  import pandas as pd
  import pytest
  from numpy.testing import assert_almost_equal
  
  ###
  # Save and Load
  ###
  
  @pytest.fixture(scope="module", autouse=True)
  def to_hdf_buffer(hdf_file_path,simulation_verysimple):
      simulation_verysimple.model.homologous_density.to_hdf(hdf_file_path, overwrite=True)
  
  def test_hdf_density_0(hdf_file_path, simulation_verysimple):
      actual = simulation_verysimple.model.homologous_density.density_0
      if hasattr(actual, 'cgs'):
          actual = actual.cgs.value
      path = os.path.join('homologous_density','density_0')
      expected = pd.read_hdf(hdf_file_path, path)
      assert_almost_equal(actual, expected.values)
  
  def test_hdf_time_0(hdf_file_path, simulation_verysimple):
      actual = simulation_verysimple.model.homologous_density.time_0
      if hasattr(actual, 'cgs'):
          actual = actual.cgs.value
      path = os.path.join('homologous_density','scalars')
      expected = pd.read_hdf(hdf_file_path, path)['time_0']
      assert_almost_equal(actual, expected)