Fix nosetest for win, py3.8

conda-recipe/vtkbone/bld.bat

@@ -30,5 +30,7 @@ set PATH=%PATH%;%PREFIX%\\Library\\lib;%PREFIX%\\Library\\bin
 set PYTHONPATH=%PYTHONPATH%;%PREFIX%\\Lib\\site-packages
 
 :: Run tests
-nosetests "%SRC_DIR%\Testing\Python"
+::    Note that for >=py3.8, DLL look up no longer goes through `PATH`.
+::    This is a hack to make nose run by adding dll's inside python
+python %RECIPE_DIR%/test_windows.py %SRC_DIR%/Testing/Python
 if errorlevel 1 exit 1

conda-recipe/vtkbone/test_windows.py

@@ -0,0 +1,27 @@
+# This is a custom implementation of nosetests for testing
+# the conda build on Python 3.8. The %PATH% variable is no
+# longer used for resolving DLLs so they must be added
+# using `os.add_dll_directory("%PATH%)"`
+#
+# Assuming %PREFIX$ is a defined environment variable
+# Pass the test to run as normal
+
+# -*- coding: utf-8 -*-
+import re
+import sys
+import os
+
+from nose import run_exit
+
+if __name__ == '__main__':
+    PREFIX = os.getenv('PREFIX')
+    if hasattr(os, 'add_dll_directory'):
+        os.add_dll_directory(os.path.join(
+            PREFIX, 'Library', 'lib'
+        ))
+        os.add_dll_directory(os.path.join(
+            PREFIX, 'Library', 'bin'
+        ))
+
+    sys.argv[0] = re.sub(r'(-script\.pyw?|\.exe)?$', '', sys.argv[0])
+    sys.exit(run_exit())