def METHOD_NAME(sphere_model):
    vtk = pytest.importorskip('vtk')
    # Set maximum number of tracks per process to write
    sphere_model.settings.max_tracks = 25
    sphere_model.settings.photon_transport = True
    # Run OpenMC to generate tracks.h5 file
    generate_track_file(sphere_model, tracks=True)
    tracks = openmc.Tracks('tracks.h5')
    polydata = tracks.write_to_vtk('tracks.vtp')
    assert isinstance(polydata, vtk.vtkPolyData)
    assert Path('tracks.vtp').is_file()