pytest:sid_strings: use hashed instead of random unique numbers

This removes the slim chance of flapping failures, and makes tracking
the created class back to the SID string theoretically possible.

To maintain uniqueness of the governs-id, we in chuck some of the
timestamp.

Signed-off-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>

python/samba/tests/sid_strings.py

@@ -16,10 +16,10 @@
 #
 
 import os
-import random
 import string
 import sys
 import time
+from hashlib import blake2b
 
 import ldb
 
@@ -81,14 +81,14 @@ class SidStringTests(TestCase):
         cls.timestamp = str(int(time.time()))
 
     def _test_sid_string_with_args(self, code, expected_sid):
-        random_suffix = random.randint(0, 100000)
+        suffix = int(blake2b(code.encode(), digest_size=3).hexdigest(), 16)
 
-        class_name = f'my-Sid-String-Class-{self.timestamp}-{random_suffix}'
+        class_name = f'my-Sid-String-Class-{self.timestamp}-{suffix}'
         class_ldap_display_name = class_name.replace('-', '')
 
         class_dn = f'CN={class_name},{self.schema_dn}'
 
-        governs_id = f'1.3.6.1.4.1.7165.4.6.2.9.{random_suffix}'
+        governs_id = f'1.3.6.1.4.1.7165.4.6.2.9.{self.timestamp[-8:]}.{suffix}'
         if expected_sid is not None:
             # Append the RID to our OID to ensure more uniqueness.
             rid = expected_sid.rsplit('-', 1)[1]
@@ -126,7 +126,7 @@ schemaUpdateNow: 1
 '''
         self.ldb.modify_ldif(ldif)
 
-        object_name = f'sddl_{self.timestamp}_{random_suffix}'
+        object_name = f'sddl_{self.timestamp}_{suffix}'
         object_dn = f'CN={object_name},{self.base_dn}'
 
         ldif = f'''