diff -r 849826a900d2 Lib/test/test_os.py
--- a/Lib/test/test_os.py	Tue Oct 25 21:49:19 2016 -0500
+++ b/Lib/test/test_os.py	Wed Oct 26 11:11:51 2016 +0300
@@ -9,7 +9,6 @@ import contextlib
 import decimal
 import errno
 import fractions
-import getpass
 import itertools
 import locale
 import mmap
@@ -44,15 +43,7 @@ try:
     import _winapi
 except ImportError:
     _winapi = None
-try:
-    import grp
-    groups = [g.gr_gid for g in grp.getgrall() if getpass.getuser() in g.gr_mem]
-    if hasattr(os, 'getgid'):
-        process_gid = os.getgid()
-        if process_gid not in groups:
-            groups.append(process_gid)
-except ImportError:
-    groups = []
+
 try:
     import pwd
     all_users = [u.pw_uid for u in pwd.getpwall()]
@@ -84,6 +75,21 @@ else:
 HAVE_WHEEL_GROUP = sys.platform.startswith('freebsd') and os.getgid() == 0
 
 
+def fmt_uid(uid):
+    try:
+        import pwd
+        return 'uid=%d(%s)' % (uid, pwd.getpwuid(uid).pw_name)
+    except (ImportError, KeyError, OSError):
+        return 'uid=%s' % uid
+
+def fmt_gid(gid):
+    try:
+        import grp
+        return 'gid=%d(%s)' % (gid, grp.getgrgid(gid).gr_name)
+    except (ImportError, KeyError, OSError):
+        return 'gid=%s' % gid
+
+
 @contextlib.contextmanager
 def ignore_deprecation_warnings(msg_regex, quiet=False):
     with support.check_warnings((msg_regex, DeprecationWarning), quiet=quiet):
@@ -1188,16 +1194,46 @@ class ChownFileTests(unittest.TestCase):
         self.assertIsNone(os.chown(support.TESTFN, uid, gid))
         self.assertIsNone(os.chown(support.TESTFN, -1, -1))
 
-    @unittest.skipUnless(len(groups) > 1, "test needs more than one group")
     def test_chown(self):
-        gid_1, gid_2 = groups[:2]
-        uid = os.stat(support.TESTFN).st_uid
+        grp = support.import_module('grp')
+        if root_in_posix:
+            groups = [g.gr_gid for g in grp.getgrall()]
+        else:
+            pwd = support.import_module('pwd')
+            user = pwd.getpwuid(os.getuid()).pw_name
+            groups = [g.gr_gid for g in grp.getgrall() if user in g.gr_mem]
+        if hasattr(os, 'getgid'):
+            process_gid = os.getgid()
+            if process_gid not in groups:
+                groups.append(process_gid)
+
+        st = os.stat(support.TESTFN)
+        uid = st.st_uid
+        gid_1 = st.st_gid
+        for gid in groups:
+            if gid != gid_1:
+                gid_2 = gid
+                break
+        else:
+            self.skipTest("test needs more than one group")
+
+        if support.verbose:
+            try:
+                print('process %s %s e%s e%s' %
+                      (fmt_uid(os.getuid()), fmt_gid(os.getgid()),
+                       fmt_uid(os.geteuid()), fmt_gid(os.getegid())))
+            except AttributeError:
+                pass
+            print('file %s %s' % (fmt_uid(uid), fmt_gid(gid_1)))
+            print('chown %s %s' % (fmt_uid(uid), fmt_gid(gid_2)))
+        os.chown(support.TESTFN, uid, gid_2)
+        gid = os.stat(support.TESTFN).st_gid
+        self.assertEqual(gid, gid_2)
+        if support.verbose:
+            print('chown %s %s' % (fmt_uid(uid), fmt_gid(gid_1)))
         os.chown(support.TESTFN, uid, gid_1)
         gid = os.stat(support.TESTFN).st_gid
         self.assertEqual(gid, gid_1)
-        os.chown(support.TESTFN, uid, gid_2)
-        gid = os.stat(support.TESTFN).st_gid
-        self.assertEqual(gid, gid_2)
 
     @unittest.skipUnless(root_in_posix and len(all_users) > 1,
                          "test needs root privilege and more than one user")
@@ -1214,11 +1250,23 @@ class ChownFileTests(unittest.TestCase):
     @unittest.skipUnless(not root_in_posix and len(all_users) > 1,
                          "test needs non-root account and more than one user")
     def test_chown_without_permission(self):
-        uid_1, uid_2 = all_users[:2]
-        gid = os.stat(support.TESTFN).st_gid
+        st = os.stat(support.TESTFN)
+        uid_1 = st.st_uid
+        gid = st.st_gid
+        for uid in all_users:
+            if uid != uid_1:
+                uid_2 = uid
+                break
+        else:
+            self.skipTest("test needs more than one user")
+
+        if support.verbose:
+            print('file %s %s' % (fmt_uid(uid_1), fmt_gid(gid)))
+            print('chown %s %s' % (fmt_uid(uid_2), fmt_gid(gid)))
         with self.assertRaises(PermissionError):
-            os.chown(support.TESTFN, uid_1, gid)
             os.chown(support.TESTFN, uid_2, gid)
+        uid = os.stat(support.TESTFN).st_uid
+        self.assertEqual(uid, uid_1)
 
     @classmethod
     def tearDownClass(cls):