From: Barry Warsaw <barry@python.org>
Date: Wed, 29 Nov 2017 15:34:40 +0000 (-0500)
Subject: [2.7] bpo-32107 - Backport bitmask check fix (GH-4576) (#4590)
X-Git-Tag: v2.7.15rc1~108
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=56e444f8df34cd502d6e3b110c90aed086883a72;p=python

[2.7] bpo-32107 - Backport bitmask check fix (GH-4576) (#4590)

Remove a flakey test and rewrite another one for readability.
---

diff --git a/Lib/test/test_uuid.py b/Lib/test/test_uuid.py
index 0a8130ee0c..3749564c93 100644
--- a/Lib/test/test_uuid.py
+++ b/Lib/test/test_uuid.py
@@ -429,54 +429,52 @@ eth0      Link encap:Ethernet  HWaddr 12:34:56:78:90:ab
             )
             self.assertEqual(mac, 0x1234567890ab)
 
-    def check_node(self, node, requires=None, network=False):
+    def check_node(self, node, requires=None):
         if requires and node is None:
             self.skipTest('requires ' + requires)
         hex = '%012x' % node
         if test_support.verbose >= 2:
             print hex + ' ',
-        if network:
-            # 47 bit will never be set in IEEE 802 addresses obtained
-            # from network cards.
-            self.assertFalse(node & 0x010000000000, hex)
         self.assertTrue(0 < node < (1L << 48),
                         "%s is not an RFC 4122 node ID" % hex)
 
     @unittest.skipUnless(os.name == 'posix', 'requires Posix')
     def test_ifconfig_getnode(self):
         node = uuid._ifconfig_getnode()
-        self.check_node(node, 'ifconfig', True)
+        self.check_node(node, 'ifconfig')
 
     @unittest.skipUnless(os.name == 'posix', 'requires Posix')
     def test_arp_getnode(self):
         node = uuid._arp_getnode()
-        self.check_node(node, 'arp', True)
+        self.check_node(node, 'arp')
 
     @unittest.skipUnless(os.name == 'posix', 'requires Posix')
     def test_lanscan_getnode(self):
         node = uuid._lanscan_getnode()
-        self.check_node(node, 'lanscan', True)
+        self.check_node(node, 'lanscan')
 
     @unittest.skipUnless(os.name == 'posix', 'requires Posix')
     def test_netstat_getnode(self):
         node = uuid._netstat_getnode()
-        self.check_node(node, 'netstat', True)
+        self.check_node(node, 'netstat')
 
     @unittest.skipUnless(os.name == 'nt', 'requires Windows')
     def test_ipconfig_getnode(self):
         node = uuid._ipconfig_getnode()
-        self.check_node(node, 'ipconfig', True)
+        self.check_node(node, 'ipconfig')
 
     @unittest.skipUnless(importable('win32wnet'), 'requires win32wnet')
     @unittest.skipUnless(importable('netbios'), 'requires netbios')
     def test_netbios_getnode(self):
         node = uuid._netbios_getnode()
-        self.check_node(node, network=True)
+        self.check_node(node)
 
     def test_random_getnode(self):
         node = uuid._random_getnode()
-        # Least significant bit of first octet must be set.
-        self.assertTrue(node & 0x010000000000, '%012x' % node)
+        # The multicast bit, i.e. the least significant bit of first octet,
+        # must be set for randomly generated MAC addresses.  See RFC 4122,
+        # $4.1.6.
+        self.assertTrue(node & (1 << 40), '%012x' % node)
         self.check_node(node)
 
     @unittest.skipUnless(os.name == 'posix', 'requires Posix')