code: def test_descriptor_sift():
      detector_extractor = SIFT(n_hist=2, n_ori=4)
      exp_descriptors = np.array(
          [
              [
                  173,
                  30,
                  55,
                  32,
                  173,
                  16,
                  45,
                  82,
                  173,
                  154,
                  170,
                  173,
                  173,
                  169,
                  65,
                  110,
              ],
              [
                  173,
                  30,
                  55,
                  32,
                  173,
                  16,
                  45,
                  82,
                  173,
                  154,
                  170,
                  173,
                  173,
                  169,
                  65,
                  110,
              ],
              [
                  189,
                  52,
                  18,
                  18,
                  189,
                  11,
                  21,
                  55,
                  189,
                  75,
                  173,
                  91,
                  189,
                  65,
                  189,
                  162,
              ],
              [
                  172,
                  156,
                  185,
                  66,
                  92,
                  76,
                  78,
                  185,
                  185,
                  87,
                  88,
                  82,
                  98,
                  56,
                  96,
                  185,
              ],
              [
                  216,
                  19,
                  40,
                  9,
                  196,
                  7,
                  57,
                  36,
                  216,
                  56,
                  158,
                  29,
                  216,
                  42,
                  144,
                  154,
              ],
              [
                  169,
                  120,
                  169,
                  91,
                  129,
                  108,
                  169,
                  67,
                  169,
                  142,
                  111,
                  95,
                  169,
                  120,
                  69,
                  41,
              ],
              [
                  199,
                  10,
                  138,
                  44,
                  178,
                  11,
                  161,
                  34,
                  199,
                  113,
                  73,
                  64,
                  199,
                  82,
                  31,
                  178,
              ],
              [
                  154,
                  56,
                  154,
                  49,
                  144,
                  154,
                  154,
                  78,
                  154,
                  51,
                  154,
                  83,
                  154,
                  154,
                  154,
                  72,
              ],
              [
                  230,
                  46,
                  47,
                  21,
                  230,
                  15,
                  65,
                  95,
                  230,
                  52,
                  72,
                  51,
                  230,
                  19,
                  59,
                  130,
              ],
              [
                  155,
                  117,
                  154,
                  102,
                  155,
                  155,
                  90,
                  110,
                  145,
                  127,
                  155,
                  50,
                  57,
                  155,
                  155,
                  70,
              ],
          ],
          dtype=np.uint8,
      )
  
      detector_extractor.detect_and_extract(img)
  
      assert_equal(exp_descriptors, detector_extractor.descriptors[:10])
  
      keypoints_count = detector_extractor.keypoints.shape[0]
      assert keypoints_count == detector_extractor.descriptors.shape[0]
      assert keypoints_count == detector_extractor.orientations.shape[0]
      assert keypoints_count == detector_extractor.octaves.shape[0]
      assert keypoints_count == detector_extractor.positions.shape[0]
      assert keypoints_count == detector_extractor.scales.shape[0]
      assert keypoints_count == detector_extractor.scales.shape[0]
  
file_path: scikit-image/skimage/feature/tests/test_sift.py
imports: import numpy
  import pytest
  from numpy.testing import assert_almost_equal, assert_equal
  from skimage import data
  from skimage._shared.testing import run_in_parallel
  from skimage.feature import SIFT
  from skimage.util.dtype import _convert
label_desc: Use image node_id 2 for calling a global function with example usage: test_descriptor_sift() without return types