The samba.tests.dsdb_schema_attributes test uses a timestamp to make unique names for schema attributes, but does not use a distinct prefix per unit test. If the test runs fast, two tests can then run in the same second, causing a failure.
This bug was referenced in samba master: 6590bb0b77c641f0d4686b39c713c1405ffb64f5
This bug was referenced in samba v4-15-test: 45b5c9074e7b9fc429d741a2920ab24a28bb2cc1
This bug was referenced in samba v4-15-stable (Release samba-4.15.0rc6): 45b5c9074e7b9fc429d741a2920ab24a28bb2cc1
This bug was referenced in samba v4-13-test: 4ada6c24a5c3c9f0924f90fc11747cd09999969f
This bug was referenced in samba v4-14-test: 78f183faa6db04e485a217bfc59f7ef3458dda7e
This bug was referenced in samba v4-13-stable (Release samba-4.13.12): 4ada6c24a5c3c9f0924f90fc11747cd09999969f
This bug was referenced in samba v4-14-stable (Release samba-4.14.8): 78f183faa6db04e485a217bfc59f7ef3458dda7e