code: def test_rotation3d_align_z_axis():
      """Test rotation3d_align_z_axis."""
      # The more complex z axis fails the assert presumably due to tolerance
      #
      inp_zs = [
          [0, 0, 1],
          [0, 1, 0],
          [1, 0, 0],
          [0, 0, -1],
          [-0.75071668, -0.62183808, 0.22302888],
      ]
  
      exp_res = [
          [[1.0, 0.0, 0.0], [0.0, 1.0, 0.0], [0.0, 0.0, 1.0]],
          [[1.0, 0.0, 0.0], [0.0, 0.0, 1.0], [0.0, -1.0, 0.0]],
          [[0.0, 0.0, 1.0], [0.0, 1.0, 0.0], [-1.0, 0.0, 0.0]],
          [[1.0, 0.0, 0.0], [0.0, -1.0, 0.0], [0.0, 0.0, -1.0]],
          [
              [0.53919688, -0.38169517, -0.75071668],
              [-0.38169517, 0.683832, -0.62183808],
              [0.75071668, 0.62183808, 0.22302888],
          ],
      ]
  
      for res, z in zip(exp_res, inp_zs):
          assert_allclose(res, rotation3d_align_z_axis(z), atol=1e-7)
  
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 13 for calling a global function with example usage: test_rotation3d_align_z_axis() without return types