code: def test_periodic_reference(dtype):
      img = data.astronaut()
      img = rgb2gray(img)
      s = np.linspace(0, 2 * np.pi, 400)
      r = 100 + 100 * np.sin(s)
      c = 220 + 100 * np.cos(s)
      init = np.array([r, c]).T
      img_smooth = gaussian(img, 3, preserve_range=False).astype(
          dtype, copy=False
      )
      snake = active_contour(
          img_smooth,
          init,
          alpha=0.015,
          beta=10,
          w_line=0,
          w_edge=1,
          gamma=0.001,
      )
      assert snake.dtype == _supported_float_type(dtype)
      refr = [98, 99, 100, 101, 102, 103, 104, 105, 106, 108]
      refc = [299, 298, 298, 298, 298, 297, 297, 296, 296, 295]
      assert_equal(np.array(snake[:10, 0], dtype=np.int32), refr)
      assert_equal(np.array(snake[:10, 1], dtype=np.int32), refc)
  
file_path: scikit-image/skimage/segmentation/tests/test_active_contour_model.py
imports: import numpy
  import pytest
  from numpy.testing import assert_equal, assert_allclose
  from skimage import data
  from skimage._shared.utils import _supported_float_type
  from skimage.color import rgb2gray
  from skimage.filters import gaussian
  from skimage.segmentation import active_contour
label_desc: Use image node_id 1 for calling a global function with example usage: test_periodic_reference(dtype) without return types