Merge pull request #1709 from radiasoft/master

uniquify paths in PYTHONPATH

changelog.d/1709.bugfix.rst

+In test.paths_on_python_path, avoid adding unnecessary duplicates to the PYTHONPATH.

setuptools/command/test.py

@@ -15,6 +15,7 @@ from pkg_resources import (resource_listdir, resource_exists, normalize_path,
                            working_set, _namespace_packages, evaluate_marker,
                            add_activation_listener, require, EntryPoint)
 from setuptools import Command
+from .build_py import _unique_everseen
 
 __metaclass__ = type
 
@@ -186,7 +187,7 @@ class test(Command):
         orig_pythonpath = os.environ.get('PYTHONPATH', nothing)
         current_pythonpath = os.environ.get('PYTHONPATH', '')
         try:
-            prefix = os.pathsep.join(paths)
+            prefix = os.pathsep.join(_unique_everseen(paths))
             to_join = filter(None, [prefix, current_pythonpath])
             new_path = os.pathsep.join(to_join)
             if new_path: