code: def test_calculate_chpi_positions_preload():
      """Test calculation of cHPI positions with and without data loaded."""
      raw = read_raw_fif(chpi_fif_fname, allow_maxshield="yes").crop(
          0, 2
      )
      kwargs = dict(t_step_min=0.1, t_window="auto", verbose=True)
      pos = compute_chpi_amplitudes(raw, **kwargs)
      raw.load_data()
      pos_preload = compute_chpi_amplitudes(raw, **kwargs)
      assert object_diff(pos, pos_preload) == ""
  
imports: from pathlib import Path
  import numpy
  import pytest
  from numpy.testing import assert_allclose, assert_array_equal, assert_array_less
  from scipy.interpolate import interp1d
  from scipy.spatial.distance import cdist
  from mne import pick_info, pick_types
  from mne._fiff.constants import FIFF
  from mne.chpi import _chpi_locs_to_times_dig, _compute_good_distances, _get_hpi_initial_fit, _setup_ext_proj, compute_chpi_amplitudes, compute_chpi_locs, compute_chpi_snr, compute_head_pos, extract_chpi_locs_ctf, extract_chpi_locs_kit, filter_chpi, get_active_chpi, get_chpi_info, head_pos_to_trans_rot_t, read_head_pos, write_head_pos
  from mne.datasets import testing
  from mne.forward._compute_forward import _MAG_FACTOR
  from mne.io import RawArray, read_info, read_raw_artemis123, read_raw_ctf, read_raw_fif, read_raw_kit
  from mne.simulation import add_chpi
  from mne.transforms import _angle_between_quats, rot_to_quat
  from mne.utils import assert_meg_snr, catch_logging, object_diff, verbose
  from mne.viz import plot_head_positions
label_desc: Use image node_id 7 for calling a global function with example usage: test_calculate_chpi_positions_preload() without return types