diff -r 71a1f53c8203 Lib/packaging/tests/support.py
--- a/Lib/packaging/tests/support.py	Wed Jul 06 07:31:38 2011 +0200
+++ b/Lib/packaging/tests/support.py	Thu Jul 07 14:30:51 2011 +0200
@@ -37,7 +37,7 @@
 from packaging import logger
 from packaging.dist import Distribution
 from packaging.tests import unittest
-from test.support import requires_zlib, unlink
+from test.support import requires_zlib, patch, unlink
 
 __all__ = ['LoggingCatcher', 'TempdirManager', 'EnvironRestorer',
            'DummyCommand', 'unittest', 'create_distribution',
@@ -266,6 +266,15 @@
         return __wrap
     return _wrap
 
+def patch_2to3(test_instance):
+    """Replaces `lib2to3.fixer_Base.BaseFix.set_filename()` with a
+    method that doesn't instantiate a new logger object to avoid
+    reference leaks."""
+    def set_filename(self, filename):
+        self.filename = filename
+    from lib2to3.fixer_base import BaseFix
+    patch(test_instance, BaseFix, "set_filename", set_filename)
+
 
 try:
     from test.support import skip_unless_symlink
diff -r 71a1f53c8203 Lib/packaging/tests/test_mixin2to3.py
--- a/Lib/packaging/tests/test_mixin2to3.py	Wed Jul 06 07:31:38 2011 +0200
+++ b/Lib/packaging/tests/test_mixin2to3.py	Thu Jul 07 14:30:51 2011 +0200
@@ -9,6 +9,10 @@
                         support.LoggingCatcher,
                         unittest.TestCase):
 
+    def setUp(self):
+        super(Mixin2to3TestCase, self).setUp()
+        support.patch_2to3(self)
+
     @unittest.skipIf(sys.version < '2.6', 'requires Python 2.6 or higher')
     def test_convert_code_only(self):
         # used to check if code gets converted properly.
diff -r 71a1f53c8203 Lib/packaging/tests/test_util.py
--- a/Lib/packaging/tests/test_util.py	Wed Jul 06 07:31:38 2011 +0200
+++ b/Lib/packaging/tests/test_util.py	Thu Jul 07 14:30:51 2011 +0200
@@ -399,6 +399,7 @@
 
     @unittest.skipIf(sys.version < '2.6', 'requires Python 2.6 or higher')
     def test_run_2to3_on_code(self):
+        support.patch_2to3(self)
         content = "print 'test'"
         converted_content = "print('test')"
         file_handle = self.mktempfile()
@@ -414,6 +415,7 @@
 
     @unittest.skipIf(sys.version < '2.6', 'requires Python 2.6 or higher')
     def test_run_2to3_on_doctests(self):
+        support.patch_2to3(self)
         # to check if text files containing doctests only get converted.
         content = ">>> print 'test'\ntest\n"
         converted_content = ">>> print('test')\ntest\n\n"