bpo-32872: Avoid regrtest compatibility issue with namespace packages. (GH-6276) (#6277)

(cherry picked from commit e52ac045)
Co-authored-by: Ned Deily <nad@python.org>

Lib/test/libregrtest/setup.py

@@ -57,7 +57,7 @@ def setup_tests(ns):
         if hasattr(module, '__path__'):
             for index, path in enumerate(module.__path__):
                 module.__path__[index] = os.path.abspath(path)
-        if hasattr(module, '__file__'):
+        if getattr(module, '__file__', None):
             module.__file__ = os.path.abspath(module.__file__)
 
     # MacOSX (a.k.a. Darwin) has a default stack size that is too small

Misc/NEWS.d/next/Tests/2018-03-28-01-35-02.bpo-32872.J5NDUj.rst

+Avoid regrtest compatibility issue with namespace packages.