text: import numpy as np
  from brainlit.napari_viterbrain.viterbrain_plugin import (
      napari_get_reader,
      comp_trace,
  )
  from brainlit.algorithms.connect_fragments.tests.test_viterbrain import create_vb
  import pickle
  
  vb = create_vb()
  vb.compute_all_costs_dist(vb.frag_frag_dist, vb.frag_soma_dist)
  vb.compute_all_costs_int()
  
  
  def test_reader(tmp_path):
      my_test_file = str(tmp_path / "viterbrain.pickle")
      with open(my_test_file, "wb") as handle:
          pickle.dump(vb, handle)
  
      # try to read it back in
      reader = napari_get_reader(my_test_file)
      assert callable(reader)
  
      # make sure we're delivering the right format
      layer_data_list = reader(my_test_file)
      assert isinstance(layer_data_list, list) and len(layer_data_list) > 0
      layer_data_tuple = layer_data_list[0]
      assert isinstance(layer_data_tuple, tuple) and len(layer_data_tuple) > 0
  
      reader = napari_get_reader("fake.file")
      assert reader is None
  
  
  # def test_example_magic_widget(make_napari_viewer, tmp_path):
  #     my_test_file = str(tmp_path / "viterbrain.pickle")
  #     with open(my_test_file, "wb") as handle:
  #         pickle.dump(vb, handle)
  
  #     viewer = make_napari_viewer()
  
  #     start_layernum = len(list(viewer.layers))
  
  #     my_widget = comp_trace()
  #     my_widget(v=viewer, start_comp=1, end_comp=5, filename=my_test_file)
  
  #     # test that a layer was added
  #     assert len(list(viewer.layers)) == start_layernum + 1
  