code: def test_merging():
      # test region merging in the post-processing step
      img = np.array([[0, 0.3], [0.7, 1]])
      # With scale=0, only the post-processing is performed.
      seg = felzenszwalb(img, scale=0, sigma=0, min_size=2)
      # we expect 2 segments:
      assert_equal(len(np.unique(seg)), 2)
      assert_array_equal(seg[0, :], 0)
      assert_array_equal(seg[1, :], 1)
  
file_path: scikit-image/skimage/segmentation/tests/test_felzenszwalb.py
imports: import numpy
  from skimage import data
  from skimage.segmentation import felzenszwalb
  from skimage._shared import testing
  from skimage._shared.testing import assert_greater, run_in_parallel, assert_equal, assert_array_equal, assert_warns, assert_no_warnings
label_desc: Use image node_id 5 for calling a global function with example usage: test_merging() without return types