code: def test_get_ras_to_neuromag_trans():
      """Test the coordinate transformation from ras to neuromag."""
      # create model points in neuromag-like space
      rng = np.random.RandomState(0)
      anterior = [0, 1, 0]
      left = [-1, 0, 0]
      right = [0.8, 0, 0]
      up = [0, 0, 1]
      rand_pts = rng.uniform(-1, 1, (3, 3))
      pts = np.vstack((anterior, left, right, up, rand_pts))
  
      # change coord system
      rx, ry, rz, tx, ty, tz = rng.uniform(-2 * np.pi, 2 * np.pi, 6)
      trans = np.dot(translation(tx, ty, tz), rotation(rx, ry, rz))
      pts_changed = apply_trans(trans, pts)
  
      # transform back into original space
      nas, lpa, rpa = pts_changed[:3]
      hsp_trans = get_ras_to_neuromag_trans(nas, lpa, rpa)
      pts_restored = apply_trans(hsp_trans, pts_changed)
  
      err = "Neuromag transformation failed"
      assert_allclose(pts_restored, pts, atol=1e-6, err_msg=err)
  
imports: import itertools
  import os
  from pathlib import Path
  import numpy
  import pytest
  from numpy.testing import assert_allclose, assert_almost_equal, assert_array_equal, assert_array_less, assert_equal
  import mne
  from mne import read_trans, write_trans
  from mne.datasets import testing
  from mne.fixes import _get_img_fdata
  from mne.io import read_info
  from mne.transforms import _angle_between_quats, _average_quats, _cart_to_sph, _compute_r2, _euler_to_quat, _find_trans, _find_vector_rotation, _fit_matched_points, _get_trans, _MatchedDisplacementFieldInterpolator, _pol_to_cart, _quat_real, _quat_to_affine, _quat_to_euler, _read_fs_xfm, _sph_to_cart, _topo_to_sph, _validate_pipeline, _write_fs_xfm, apply_trans, combine_transforms, get_ras_to_neuromag_trans, invert_transform, quat_to_rot, rot_to_quat, rotation, rotation3d, rotation3d_align_z_axis, rotation_angles, translation
  from mne.transforms import _SphericalSurfaceWarp
label_desc: Use image node_id 4 for calling a global function with example usage: test_get_ras_to_neuromag_trans() without return types