docstr: Test diamond footprints
docstr_tok: ["Test","diamond","footprints"]
code: def test_footprint_diamond(self):
      """Test diamond footprints"""
      self.strel_worker(
          "data/diamond-matlab-output.npz", footprints.diamond
      )
  
imports: import numpy
  import pytest
  from numpy.testing import assert_equal
  from skimage._shared.testing import fetch
  from skimage.morphology import footprints
label_desc: Use image node_id 7 for calling the TestFootprints obj's underlying member method code with example usage: obj.test_footprint_diamond() without return types