diff --git a/Lib/test/test_uuid.py b/Lib/test/test_uuid.py
index f21bd6dfa15235..32881e51a59a7c 100644
--- a/Lib/test/test_uuid.py
+++ b/Lib/test/test_uuid.py
@@ -18,10 +18,22 @@ def importable(name):
     except:
         return False
 
-
-class BaseTestUUID:
+class _BaseTestShared:
     uuid = None
 
+    def check_node(self, node, requires=None):
+        if requires and node is None:
+            self.skipTest('requires ' + requires)
+        hex = '%012x' % node
+        if support.verbose >= 2:
+            print(hex, end=' ')
+        self.assertTrue(0 <= node < (1 << 48),
+                        "%s is not an RFC 4122 node ID" % hex)
+
+
+
+class BaseTestUUID(_BaseTestShared):
+
     def test_UUID(self):
         equal = self.assertEqual
         ascending = []
@@ -305,7 +317,7 @@ def test_exceptions(self):
 
     def test_getnode(self):
         node1 = self.uuid.getnode()
-        self.assertTrue(0 < node1 < (1 << 48), '%012x' % node1)
+        self.check_node(node1)
 
         # Test it again to ensure consistency.
         node2 = self.uuid.getnode()
@@ -485,8 +497,7 @@ class TestUUIDWithExtModule(BaseTestUUID, unittest.TestCase):
     uuid = c_uuid
 
 
-class BaseTestInternals:
-    uuid = None
+class BaseTestInternals(_BaseTestShared):
 
     @unittest.skipUnless(os.name == 'posix', 'requires Posix')
     def test_find_mac(self):
@@ -512,15 +523,6 @@ def test_find_mac(self):
 
         self.assertEqual(mac, 0x1234567890ab)
 
-    def check_node(self, node, requires=None):
-        if requires and node is None:
-            self.skipTest('requires ' + requires)
-        hex = '%012x' % node
-        if support.verbose >= 2:
-            print(hex, end=' ')
-        self.assertTrue(0 < node < (1 << 48),
-                        "%s is not an RFC 4122 node ID" % hex)
-
     @unittest.skipUnless(os.name == 'posix', 'requires Posix')
     def test_ifconfig_getnode(self):
         node = self.uuid._ifconfig_getnode()