code: def test_get_active_chpi_neuromag():
      """Test extracting of cHPI positions from neuromag data."""
      raw = read_raw_fif(
          chpi_fif_fname, allow_maxshield="yes", preload=True
      )
      status_ch = raw.ch_names.index("STI201")
  
      # make artificial chpi signal
      first_three_on = 256 + 512 + 1024
      all_on = 256 + 512 + 1024 + 2048 + 4096
      raw._data[status_ch][:1000] = 0
      raw._data[status_ch][1000:2000] = first_three_on
      raw._data[status_ch][2000:] = all_on
  
      # build target signal
      target_signal = 5 * np.ones_like(raw.times)
      target_signal[:1000] = 0
      target_signal[1000:2000] = 3
  
      assert_allclose(
          get_active_chpi(raw, on_missing="ignore"), target_signal
      )
  
      raw_no_chpi = read_raw_fif(sample_fname)
      assert_allclose(
          get_active_chpi(raw_no_chpi, on_missing="ignore"),
          np.zeros_like(raw_no_chpi.times),
      )
  
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 24 for calling a global function with example usage: test_get_active_chpi_neuromag() without return types