class_docstr: Test the Tamura Texture features programmed in medpy.features.texture.
  Functions are:  coarseness(image, voxelspacing = None, mask = slice(None))
                  contrast(image, mask = slice(None))
                  directionality(image, voxelspacing = None, mask = slice(None), min_distance = 4)
code: def setUp(self):
      self.image1 = numpy.zeros([100, 100])
      self.image1[:, ::3] = 1
      self.voxelspacing1 = (1.0, 3.0)
      self.mask1 = [slice(0, 50, 1), slice(0, 50, 1)]
  
file_path: medpy/tests/features_/texture.py
imports: import unittest
  from medpy.features.texture import *
label_desc: Use image node_id 1 for calling the TestTextureFeatures obj's underlying member method code with example usage: obj.setUp() without return types