code: def test_subpix_border():
      img = np.zeros((50, 50))
      img[1:25, 1:25] = 255
      img[25:-1, 25:-1] = 255
      corner = corner_peaks(corner_harris(img), threshold_rel=0)
      subpix = corner_subpix(img, corner, window_size=11)
      ref = np.array(
          [
              [24.5, 24.5],
              [0.52040816, 0.52040816],
              [0.52040816, 24.47959184],
              [24.47959184, 0.52040816],
              [24.52040816, 48.47959184],
              [48.47959184, 24.52040816],
              [48.47959184, 48.47959184],
          ]
      )
  
      assert_almost_equal(subpix, ref)
  
imports: import numpy
  import pytest
  from numpy.testing import assert_almost_equal, assert_array_equal, assert_equal
  from skimage import data, draw, img_as_float
  from skimage._shared._warnings import expected_warnings
  from skimage._shared.testing import run_in_parallel
  from skimage._shared.utils import _supported_float_type
  from skimage.color import rgb2gray
  from skimage.feature import corner_fast, corner_foerstner, corner_harris, corner_kitchen_rosenfeld, corner_moravec, corner_orientations, corner_peaks, corner_shi_tomasi, corner_subpix, hessian_matrix, hessian_matrix_det, hessian_matrix_eigvals, peak_local_max, shape_index, structure_tensor, structure_tensor_eigenvalues
  from skimage.morphology import cube, octagon
label_desc: Use image node_id 27 for calling a global function with example usage: test_subpix_border() without return types