new_contents: from __future__ import print_function, division, absolute_import
  
  import warnings
  import sys
  # unittest only added in 3.4 self.subTest()
  if sys.version_info[0] < 3 or sys.version_info[1] < 4:
      import unittest2 as unittest
  else:
      import unittest
  # unittest.mock is not available in 2.7 (though unittest2 might contain it?)
  try:
      import unittest.mock as mock
  except ImportError:
      import mock
  
  import matplotlib
  matplotlib.use('Agg')  # fix execution of tests involving matplotlib on travis
  import numpy as np
  
  import imgaug.augmenters as iaa
  import imgaug.augmenters.overlay as overlay
  
  
  class Test_blend_alpha(unittest.TestCase):
      def test_warns_that_it_is_deprecated(self):
          image_fg = np.zeros((1, 1, 3), dtype=np.uint8)
          image_bg = np.copy(image_fg)
          alpha = 1
  
          with warnings.catch_warnings(record=True) as caught_warnings:
              warnings.simplefilter("always")
              _ = overlay.blend_alpha(image_fg, image_bg, alpha)
  
          assert len(caught_warnings) == 1
          assert (
              "imgaug.augmenters.blend.blend_alpha"
              in str(caught_warnings[-1].message)
          )
  
  
  class TestAlpha(unittest.TestCase):
      def test_warns_that_it_is_deprecated(self):
          children_fg = iaa.Noop()
          factor = 1
  
          with warnings.catch_warnings(record=True) as caught_warnings:
              warnings.simplefilter("always")
              _ = overlay.Alpha(factor, children_fg)
  
          assert len(caught_warnings) == 1
          assert (
              "imgaug.augmenters.blend.Alpha"
              in str(caught_warnings[-1].message)
          )
  
  
  class TestAlphaElementwise(unittest.TestCase):
      def test_warns_that_it_is_deprecated(self):
          children_fg = iaa.Noop()
          factor = 1
  
          with warnings.catch_warnings(record=True) as caught_warnings:
              warnings.simplefilter("always")
              _ = overlay.AlphaElementwise(factor, children_fg)
  
          assert len(caught_warnings) == 1
          assert (
              "imgaug.augmenters.blend.AlphaElementwise"
              in str(caught_warnings[-1].message)
          )
  
  
  class TestSimplexNoiseAlpha(unittest.TestCase):
      def test_warns_that_it_is_deprecated(self):
          children_fg = iaa.Noop()
  
          with warnings.catch_warnings(record=True) as caught_warnings:
              warnings.simplefilter("always")
              _ = overlay.SimplexNoiseAlpha(children_fg)
  
          assert len(caught_warnings) == 1
          assert (
              "imgaug.augmenters.blend.SimplexNoiseAlpha"
              in str(caught_warnings[-1].message)
          )
  
  
  class TestFrequencyNoiseAlpha(unittest.TestCase):
      def test_warns_that_it_is_deprecated(self):
          children_fg = iaa.Noop()
  
          with warnings.catch_warnings(record=True) as caught_warnings:
              warnings.simplefilter("always")
              _ = overlay.FrequencyNoiseAlpha(first=children_fg)
  
          assert len(caught_warnings) == 1
          assert (
              "imgaug.augmenters.blend.FrequencyNoiseAlpha"
              in str(caught_warnings[-1].message)
          )
  
subject: Add tests for old overlay module