add uniqueness test

Author: picnixz

Lib/test/test_uuid.py

@@ -706,6 +706,14 @@ def test_uuid8(self):
             if lo is not None:
                 equal(u.int & 0x3fffffffffffffff, lo)
 
+    def test_uuid8_uniqueness(self):
+        """Test that UUIDv8-generated values are unique (up to a negligible
+        probability of failure)."""
+        u1 = self.uuid.uuid8()
+        u2 = self.uuid.uuid8()
+        self.assertNotEqual(u1.int, u2.int)
+        self.assertEqual(u1.version, u2.version)
+
     @support.requires_fork()
     def testIssue8621(self):
         # On at least some versions of OSX self.uuid.uuid4 generates