diff --git a/Lib/packaging/tests/__main__.py b/Lib/packaging/tests/__main__.py
index 51daba4..00f323e 100644
--- a/Lib/packaging/tests/__main__.py
+++ b/Lib/packaging/tests/__main__.py
@@ -3,7 +3,6 @@
 # Ripped from importlib tests, thanks Brett!
 
 import os
-import sys
 import unittest
 from test.support import run_unittest, reap_children, reap_threads
 
diff --git a/Lib/packaging/tests/test_command_clean.py b/Lib/packaging/tests/test_command_clean.py
index 8d29e4d..ab944ed 100644
--- a/Lib/packaging/tests/test_command_clean.py
+++ b/Lib/packaging/tests/test_command_clean.py
@@ -23,7 +23,7 @@
             if name == 'build_base':
                 continue
             for f in ('one', 'two', 'three'):
-                self.write_file(os.path.join(path, f))
+                self.write_file((path, f))
 
         # let's run the command
         cmd.all = True
diff --git a/Lib/packaging/tests/test_command_install_data.py b/Lib/packaging/tests/test_command_install_data.py
index 44a14d2..7f4af41 100644
--- a/Lib/packaging/tests/test_command_install_data.py
+++ b/Lib/packaging/tests/test_command_install_data.py
@@ -117,6 +117,11 @@
         dist.command_obj['install_distinfo'] = cmd
         cmd.run()
 
+        # first a few sanity checks
+        self.assertEqual(os.listdir(scripts_dir), ['spamd'])
+        self.assertEqual(os.listdir(install_dir), ['Spamlib-0.1.dist-info'])
+
+        # now the real test
         fn = os.path.join(install_dir, 'Spamlib-0.1.dist-info', 'RESOURCES')
         with open(fn, encoding='utf-8') as fp:
             content = fp.read().strip()
diff --git a/Lib/packaging/tests/test_command_install_dist.py b/Lib/packaging/tests/test_command_install_dist.py
index 496a3d8..3345d2e 100644
--- a/Lib/packaging/tests/test_command_install_dist.py
+++ b/Lib/packaging/tests/test_command_install_dist.py
@@ -93,21 +93,20 @@
         self.old_expand = os.path.expanduser
         os.path.expanduser = _expanduser
 
-        try:
-            # this is the actual test
-            self._test_user_site()
-        finally:
+        def cleanup():
             _CONFIG_VARS['userbase'] = self.old_user_base
             _SCHEMES.set(scheme, 'purelib', self.old_user_site)
             os.path.expanduser = self.old_expand
 
-    def _test_user_site(self):
+        self.addCleanup(cleanup)
+
         schemes = get_scheme_names()
         for key in ('nt_user', 'posix_user', 'os2_home'):
             self.assertIn(key, schemes)
 
         dist = Distribution({'name': 'xx'})
         cmd = install_dist(dist)
+
         # making sure the user option is there
         options = [name for name, short, lable in
                    cmd.user_options]
diff --git a/Lib/packaging/tests/test_command_test.py b/Lib/packaging/tests/test_command_test.py
index 31566eb..7aa1f79 100644
--- a/Lib/packaging/tests/test_command_test.py
+++ b/Lib/packaging/tests/test_command_test.py
@@ -139,7 +139,8 @@
         cmd.run()
         self.assertEqual(['build has run'], record)
 
-    def _test_works_with_2to3(self):
+    @unittest.skip('needs to be written')
+    def test_works_with_2to3(self):
         pass
 
     def test_checks_requires(self):
diff --git a/Lib/packaging/tests/test_command_upload.py b/Lib/packaging/tests/test_command_upload.py
index 82d7360..1f68c1d 100644
--- a/Lib/packaging/tests/test_command_upload.py
+++ b/Lib/packaging/tests/test_command_upload.py
@@ -129,7 +129,7 @@
         dist_files = [(command, pyversion, filename)]
         docs_path = os.path.join(self.tmp_dir, "build", "docs")
         os.makedirs(docs_path)
-        self.write_file(os.path.join(docs_path, "index.html"), "yellow")
+        self.write_file((docs_path, "index.html"), "yellow")
         self.write_file(self.rc, PYPIRC)
 
         # let's run it
diff --git a/Lib/packaging/tests/test_command_upload_docs.py b/Lib/packaging/tests/test_command_upload_docs.py
index 4162e2a..803e733 100644
--- a/Lib/packaging/tests/test_command_upload_docs.py
+++ b/Lib/packaging/tests/test_command_upload_docs.py
@@ -71,9 +71,8 @@
         if sample_dir is None:
             sample_dir = self.mkdtemp()
         os.mkdir(os.path.join(sample_dir, "docs"))
-        self.write_file(os.path.join(sample_dir, "docs", "index.html"),
-                        "Ce mortel ennui")
-        self.write_file(os.path.join(sample_dir, "index.html"), "Oh la la")
+        self.write_file((sample_dir, "docs", "index.html"), "Ce mortel ennui")
+        self.write_file((sample_dir, "index.html"), "Oh la la")
         return sample_dir
 
     def test_zip_dir(self):
diff --git a/Lib/packaging/tests/test_create.py b/Lib/packaging/tests/test_create.py
index b896619..16dbfb7 100644
--- a/Lib/packaging/tests/test_create.py
+++ b/Lib/packaging/tests/test_create.py
@@ -80,8 +80,7 @@
             os.mkdir(os.path.join(tempdir, dir_))
 
         for file_ in files:
-            path = os.path.join(tempdir, file_)
-            self.write_file(path, 'xxx')
+            self.write_file((tempdir, file_), 'xxx')
 
         mainprogram._find_files()
         mainprogram.data['packages'].sort()
diff --git a/Lib/packaging/tests/test_dist.py b/Lib/packaging/tests/test_dist.py
index de68961..3089f36 100644
--- a/Lib/packaging/tests/test_dist.py
+++ b/Lib/packaging/tests/test_dist.py
@@ -6,7 +6,7 @@
 import packaging.dist
 
 from packaging.dist import Distribution
-from packaging.command import set_command
+from packaging.command import set_command, _COMMANDS
 from packaging.command.cmd import Command
 from packaging.errors import PackagingModuleError, PackagingOptionError
 from packaging.tests import captured_stdout
@@ -28,6 +28,9 @@
     def finalize_options(self):
         pass
 
+    def run(self):
+        pass
+
 
 class DistributionTestCase(support.TempdirManager,
                            support.LoggingCatcher,
@@ -38,12 +41,18 @@
 
     def setUp(self):
         super(DistributionTestCase, self).setUp()
+        # XXX this is ugly, we should fix the functions to accept args
+        # (defaulting to sys.argv)
         self.argv = sys.argv, sys.argv[:]
         del sys.argv[1:]
+        self._commands = _COMMANDS.copy()
 
     def tearDown(self):
         sys.argv = self.argv[0]
         sys.argv[:] = self.argv[1]
+        # XXX maybe we need a public API to remove commands
+        _COMMANDS.clear()
+        _COMMANDS.update(self._commands)
         super(DistributionTestCase, self).tearDown()
 
     @unittest.skip('needs to be updated')
diff --git a/Lib/packaging/tests/test_mixin2to3.py b/Lib/packaging/tests/test_mixin2to3.py
index 14a7487..000a992 100644
--- a/Lib/packaging/tests/test_mixin2to3.py
+++ b/Lib/packaging/tests/test_mixin2to3.py
@@ -1,4 +1,3 @@
-import sys
 import textwrap
 
 from packaging.tests import unittest, support
diff --git a/Lib/packaging/tests/test_uninstall.py b/Lib/packaging/tests/test_uninstall.py
index 8f094f4..2168b6f 100644
--- a/Lib/packaging/tests/test_uninstall.py
+++ b/Lib/packaging/tests/test_uninstall.py
@@ -61,8 +61,7 @@
         kw['pkg'] = pkg
 
         pkg_dir = os.path.join(project_dir, pkg)
-        os.mkdir(pkg_dir)
-        os.mkdir(os.path.join(pkg_dir, 'sub'))
+        os.makedirs(os.path.join(pkg_dir, 'sub'))
 
         self.write_file((project_dir, 'setup.cfg'), SETUP_CFG % kw)
         self.write_file((pkg_dir, '__init__.py'), '#')
diff --git a/Lib/packaging/tests/test_util.py b/Lib/packaging/tests/test_util.py
index 4d8614a..92aa72a 100644
--- a/Lib/packaging/tests/test_util.py
+++ b/Lib/packaging/tests/test_util.py
@@ -356,24 +356,20 @@
         #
         root = self.mkdtemp()
         pkg1 = os.path.join(root, 'pkg1')
-        os.mkdir(pkg1)
-        self.write_file(os.path.join(pkg1, '__init__.py'))
-        os.mkdir(os.path.join(pkg1, 'pkg2'))
-        self.write_file(os.path.join(pkg1, 'pkg2', '__init__.py'))
-        os.mkdir(os.path.join(pkg1, 'pkg3'))
-        self.write_file(os.path.join(pkg1, 'pkg3', '__init__.py'))
-        os.mkdir(os.path.join(pkg1, 'pkg3', 'pkg6'))
-        self.write_file(os.path.join(pkg1, 'pkg3', 'pkg6', '__init__.py'))
-        os.mkdir(os.path.join(pkg1, 'pkg4'))
-        os.mkdir(os.path.join(pkg1, 'pkg4', 'pkg8'))
-        self.write_file(os.path.join(pkg1, 'pkg4', 'pkg8', '__init__.py'))
-        pkg5 = os.path.join(root, 'pkg5')
-        os.mkdir(pkg5)
-        self.write_file(os.path.join(pkg5, '__init__.py'))
+        os.makedirs(os.path.join(pkg1, 'pkg2'))
+        os.makedirs(os.path.join(pkg1, 'pkg3', 'pkg6'))
+        os.makedirs(os.path.join(pkg1, 'pkg4', 'pkg8'))
+        os.makedirs(os.path.join(root, 'pkg5'))
+        self.write_file((pkg1, '__init__.py'))
+        self.write_file((pkg1, 'pkg2', '__init__.py'))
+        self.write_file((pkg1, 'pkg3', '__init__.py'))
+        self.write_file((pkg1, 'pkg3', 'pkg6', '__init__.py'))
+        self.write_file((pkg1, 'pkg4', 'pkg8', '__init__.py'))
+        self.write_file((root, 'pkg5', '__init__.py'))
 
         res = find_packages([root], ['pkg1.pkg2'])
-        self.assertEqual(set(res), set(['pkg1', 'pkg5', 'pkg1.pkg3',
-                                        'pkg1.pkg3.pkg6']))
+        self.assertEqual(sorted(res),
+                         ['pkg1', 'pkg1.pkg3', 'pkg1.pkg3.pkg6', 'pkg5'])
 
     def test_resolve_name(self):
         # test raw module name
diff --git a/Lib/packaging/tests/test_version.py b/Lib/packaging/tests/test_version.py
index 2c86111..c863362 100644
--- a/Lib/packaging/tests/test_version.py
+++ b/Lib/packaging/tests/test_version.py
@@ -1,6 +1,5 @@
 """Tests for packaging.version."""
 import doctest
-import os
 
 from packaging.version import NormalizedVersion as V
 from packaging.version import HugeMajorVersionNumError, IrrationalVersionError
@@ -46,7 +45,6 @@
     def test_from_parts(self):
 
         for v, s in self.versions:
-            parts = v.parts
             v2 = V.from_parts(*v.parts)
             self.assertEqual(v, v2)
             self.assertEqual(str(v), str(v2))
@@ -192,7 +190,7 @@
                       'Hey (>=2.5,<2.7)')
 
         for predicate in predicates:
-            v = VersionPredicate(predicate)
+            VersionPredicate(predicate)
 
         self.assertTrue(VersionPredicate('Hey (>=2.5,<2.7)').match('2.6'))
         self.assertTrue(VersionPredicate('Ho').match('2.6'))