diff -r 9b359b6c9a39 Lib/test/test_pkgutil.py
--- a/Lib/test/test_pkgutil.py	Sun Jul 08 00:45:33 2012 +1000
+++ b/Lib/test/test_pkgutil.py	Mon Jul 09 07:08:17 2012 -0700
@@ -1,11 +1,16 @@
-from test.support import run_unittest
+from contextlib import contextmanager
 import unittest
 import sys
 import imp
+# TODO: replace the next line "import pkgutil" with the appropriate
+#   form of "from pkgutil import ...".
 import pkgutil
+from pkgutil import ImpImporter
 import os
 import os.path
 import tempfile
+from test import support
+from test.support import run_unittest
 import shutil
 import zipfile
 
@@ -138,6 +143,51 @@
         del sys.modules['foo']
 
 
+class ImpImporterTests(unittest.TestCase):
+
+    def _create_file(self, path):
+        """Create a file."""
+        f = open(path, 'w')
+        f.close()
+
+    def _create_package(self, package_name):
+        """Create a package with an __init__.py."""
+        os.mkdir(package_name)
+        init_file_name = '__init__' + os.extsep + 'py'
+        init_file_path = os.path.join(package_name, init_file_name)
+        self._create_file(init_file_path)
+
+    @contextmanager
+    def new_sys_path(self):
+        """Set sys.path to a list containing a temp working directory.
+
+        """
+        with support.temp_cwd(support.TESTFN) as cwd:
+            original_sys_path = sys.path
+            sys.path = [cwd]
+            try:
+                yield
+            finally:
+                sys.path = original_sys_path
+
+    def test_iter_modules(self):
+        importer = ImpImporter()
+        with self.new_sys_path():
+            self._create_file('mymodule.py')
+            self._create_package('mypackage')
+            modules = list(importer.iter_modules())
+        self.assertEqual(modules, [('mymodule', False), ('mypackage', True)])
+
+    def test_iter_modules__with_prefix(self):
+        importer = ImpImporter()
+        with self.new_sys_path():
+            self._create_file('mymodule.py')
+            self._create_package('mypackage')
+            modules = list(importer.iter_modules(prefix='prefix.'))
+        self.assertEqual(modules, [('prefix.mymodule', False),
+                                   ('prefix.mypackage', True)])
+
+
 # These tests, especially the setup and cleanup, are hideous. They
 # need to be cleaned up once issue 14715 is addressed.
 class ExtendPathTests(unittest.TestCase):
@@ -215,7 +265,7 @@
 
 
 def test_main():
-    run_unittest(PkgutilTests, PkgutilPEP302Tests, ExtendPathTests)
+    run_unittest(PkgutilTests, PkgutilPEP302Tests, ExtendPathTests, ImpImporterTests)
     # this is necessary if test is run repeated (like when finding leaks)
     import zipimport
     zipimport._zip_directory_cache.clear()