BUG: Address memory leak in GetImageFromArray

Test based off suggestion from Roy Harnish in

 http://public.kitware.com/pipermail/insight-users/2016-September/053788.html

include/itkPyBuffer.hxx

@@ -153,6 +153,8 @@ PyBuffer<TImage>
   OutputImagePointer output = importer->GetOutput();
   output->DisconnectPipeline();
 
+  PyBuffer_Release(&pyBuffer);
+
   return output;
 }
 

test/CMakeLists.txt

@@ -13,7 +13,10 @@
 #  COMMAND BridgeNumPyTestDriver itkPyBufferTest)
 message("+++++++++" ${CMAKE_CURRENT_SOURCE_DIR})
 if(ITK_WRAP_PYTHON)
-  itk_python_add_test(NAME DicomSliceReadPythonTest
+  itk_python_add_test(NAME itkDicomSliceReadPythonTest
                       COMMAND ${CMAKE_CURRENT_SOURCE_DIR}/itkPyBufferTest.py
-                     )
+  )
+  itk_python_add_test(NAME itkPyBufferMemoryLeakTest
+    COMMAND ${CMAKE_CURRENT_SOURCE_DIR}/itkPyBufferMemoryLeakTest.py
+  )
 endif()

test/itkPyBufferMemoryLeakTest.py

@@ -0,0 +1,63 @@
+#==========================================================================
+#
+#   Copyright Insight Software Consortium
+#
+#   Licensed under the Apache License, Version 2.0 (the "License");
+#   you may not use this file except in compliance with the License.
+#   You may obtain a copy of the License at
+#
+#          http://www.apache.org/licenses/LICENSE-2.0.txt
+#
+#   Unless required by applicable law or agreed to in writing, software
+#   distributed under the License is distributed on an "AS IS" BASIS,
+#   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#   See the License for the specific language governing permissions and
+#   limitations under the License.
+#
+#==========================================================================*/
+import sys
+try:
+    import numpy as np
+except ImportError:
+    # We don't have numpy -- bail
+    sys.exit(0)
+import itk
+import resource
+
+ImageType = itk.Image[itk.F, 3]
+converter = itk.PyBuffer[ImageType]
+
+# adding +1 to numpy created once
+inputNumpyVolume = np.ones([100,100,100], dtype=np.float32)
+n = 10
+M = []
+X = range(n)
+for i in range(n):
+    inputNumpyVolume += 1
+    inputVolume = converter.GetImageFromArray(inputNumpyVolume)
+    M.append(resource.getrusage(resource.RUSAGE_SELF).ru_maxrss)
+
+if M[5] - M[4] > 1000:
+    print('Memory leak!')
+    sys.exit(1)
+
+# creating new numpy volume each time
+M = []
+X = [x + n for x in range(n)]
+for i in range(n):
+    inputNumpyVolume = np.ones([100,100,100], dtype=np.float32)
+    inputVolume = converter.GetImageFromArray(inputNumpyVolume)
+    M.append(resource.getrusage(resource.RUSAGE_SELF).ru_maxrss)
+if M[5] - M[4] > 1000:
+    print('Memory leak!')
+    sys.exit(1)
+
+# creating new numpy volume but not calling converter.GetImageFromArray(inputNumpyVolume)
+M = []
+X = [x + 2*n for x in range(n)]
+for i in range(n):
+    inputNumpyVolume = np.ones([100,100,100], dtype=np.float32)
+    M.append(resource.getrusage(resource.RUSAGE_SELF).ru_maxrss)
+if M[5] - M[4] > 1000:
+    print('Memory leak!')
+    sys.exit(1)