Python does not expect the build system to already have a 'pkg' module, and it may well have if it's an IPS image. diff -wpruN --no-dereference '--exclude=*.orig' a~/Lib/test/test_pkgutil.py a/Lib/test/test_pkgutil.py --- a~/Lib/test/test_pkgutil.py 1970-01-01 00:00:00 +++ a/Lib/test/test_pkgutil.py 1970-01-01 00:00:00 @@ -582,22 +582,22 @@ class NestedNamespacePackageTest(unittes pkgutil_boilerplate = ( 'import pkgutil; ' '__path__ = pkgutil.extend_path(__path__, __name__)') - self.create_module('a.pkg.__init__', pkgutil_boilerplate) - self.create_module('b.pkg.__init__', pkgutil_boilerplate) - self.create_module('a.pkg.subpkg.__init__', pkgutil_boilerplate) - self.create_module('b.pkg.subpkg.__init__', pkgutil_boilerplate) - self.create_module('a.pkg.subpkg.c', 'c = 1') - self.create_module('b.pkg.subpkg.d', 'd = 2') + self.create_module('a._pkg.__init__', pkgutil_boilerplate) + self.create_module('b._pkg.__init__', pkgutil_boilerplate) + self.create_module('a._pkg.subpkg.__init__', pkgutil_boilerplate) + self.create_module('b._pkg.subpkg.__init__', pkgutil_boilerplate) + self.create_module('a._pkg.subpkg.c', 'c = 1') + self.create_module('b._pkg.subpkg.d', 'd = 2') sys.path.insert(0, os.path.join(self.basedir, 'a')) sys.path.insert(0, os.path.join(self.basedir, 'b')) - import pkg - self.addCleanup(unload, 'pkg') - self.assertEqual(len(pkg.__path__), 2) - import pkg.subpkg - self.addCleanup(unload, 'pkg.subpkg') - self.assertEqual(len(pkg.subpkg.__path__), 2) - from pkg.subpkg.c import c - from pkg.subpkg.d import d + import _pkg + self.addCleanup(unload, '_pkg') + self.assertEqual(len(_pkg.__path__), 2) + import _pkg.subpkg + self.addCleanup(unload, '_pkg.subpkg') + self.assertEqual(len(_pkg.subpkg.__path__), 2) + from _pkg.subpkg.c import c + from _pkg.subpkg.d import d self.assertEqual(c, 1) self.assertEqual(d, 2)