autobuild[sn-devel-184]: intermittent test failure detected

[autobuild]

The autobuild test system (on sn-devel-184) has detected an intermittent failing test in 
the current master tree.

The autobuild log of the failure is available here:

   https://git.samba.org/autobuild.flakey.sn-devel-184/2019-05-31-0414/flakey.log

The failure seems to be in the "samba-ad-dc-ntvfs" suite, whose build logs are available here:

   https://git.samba.org/autobuild.flakey.sn-devel-184/2019-05-31-0414/samba-ad-dc-ntvfs.stderr
   https://git.samba.org/autobuild.flakey.sn-devel-184/2019-05-31-0414/samba-ad-dc-ntvfs.stdout
  
The top commit at the time of the failure was:

commit 9a2c9834cb1b77547b8b932c35870301afb9fc25
Author: Ralph Boehme <slow at samba.org>
Date:   Fri May 24 15:15:59 2019 +0200

    vfs_fruit: remove a now unnecessary include
    
    Bug: https://bugzilla.samba.org/show_bug.cgi?id=13968
    
    Signed-off-by: Ralph Boehme <slow at samba.org>
    Reviewed-by: Jeremy Allison <jra at samba.org>
    
    Autobuild-User(master): Jeremy Allison <jra at samba.org>
    Autobuild-Date(master): Thu May 30 22:12:50 UTC 2019 on sn-devel-184

and the last 50 lines of the stdout log were:

[216(859)/253 at 27m56s] samba4.smb.signing on with -k yes --signing=required(ad_dc_ntvfs)
[217(860)/253 at 27m57s] samba4.smb.signing on with -k yes --option=gensec:fake_gssapi_krb5=yes --option=gensec:gssapi_krb5=no --signing=on(ad_dc_ntvfs)
[218(861)/253 at 27m58s] samba4.smb.signing on with -k yes --option=gensec:fake_gssapi_krb5=yes --option=gensec:gssapi_krb5=no --signing=required(ad_dc_ntvfs)
[219(862)/253 at 27m59s] samba4.smb.signing --signing=yes anon(ad_dc_ntvfs)
[220(863)/253 at 27m59s] samba4.smb.signing --signing=required anon(ad_dc_ntvfs)
[221(864)/253 at 28m0s] samba.tests.complex_expressions(ad_dc_ntvfs)
[222(886)/253 at 28m11s] samba.tests.samba_tool.gpo(ad_dc_ntvfs:local)
[223(898)/253 at 29m16s] samba.tests.dcerpc.registry(ad_dc_ntvfs:local)
[224(901)/253 at 29m17s] samba.tests.dcerpc.dnsserver(ad_dc_ntvfs)
[225(918)/253 at 29m46s] samba.tests.auth_log(ad_dc_ntvfs:local)
[226(965)/253 at 30m6s] samba.tests.auth_log_pass_change(ad_dc_ntvfs)
[227(973)/253 at 30m18s] samba.tests.auth_log_ncalrpc(ad_dc_ntvfs:local)
[228(975)/253 at 30m19s] samba.tests.auth_log_samlogon(ad_dc_ntvfs:local)
[229(976)/253 at 30m20s] samba.tests.auth_log_netlogon(ad_dc_ntvfs:local)
[230(977)/253 at 30m22s] samba.tests.auth_log_netlogon_bad_creds(ad_dc_ntvfs:local)
[231(981)/253 at 30m26s] samba.tests.password_hash_fl2008(ad_dc_ntvfs:local)
[232(985)/253 at 30m31s] samba.tests.krb5_credentials(ad_dc_ntvfs)
[233(988)/253 at 30m35s] samba.tests.py_credentials(ad_dc_ntvfs)
[234(996)/253 at 30m44s] samba.tests.emulate.traffic(ad_dc_ntvfs)
[235(998)/253 at 30m45s] samba.tests.emulate.traffic_packet(ad_dc_ntvfs)
[236(1087)/253 at 33m10s] samba.tests.blackbox.traffic_replay(ad_dc_ntvfs)
[237(1092)/253 at 33m54s] samba.tests.blackbox.traffic_learner(ad_dc_ntvfs)
[238(1094)/253 at 33m57s] samba.tests.blackbox.traffic_summary(ad_dc_ntvfs)
[239(1094)/253 at 33m58s] samba.tests.blackbox.smbcontrol(ad_dc_ntvfs:local)
[240(1096)/253 at 34m1s] samba4.urgent_replication.python(ad_dc_ntvfs)(ad_dc_ntvfs:local)
[241(1104)/253 at 34m11s] samba4.ldap.match_rules.python(ad_dc_ntvfs)
[242(1138)/253 at 34m50s] samba4.ldap.notification.python(ad_dc_ntvfs)(ad_dc_ntvfs)
UNEXPECTED(failure): samba4.ldap.notification.python(ad_dc_ntvfs).__main__.LDAPNotificationTest.test_simple_search(ad_dc_ntvfs)
REASON: Exception: Exception: Traceback (most recent call last):
  File "/memdisk/autobuild/fl/b1504733/samba-ad-dc-ntvfs/source4/dsdb/tests/python/notification.py", line 150, in test_simple_search
    self.assertIsNotNone(msg3)
AssertionError: unexpectedly None

FAILED (1 failures, 0 errors and 0 unexpected successes in 0 testsuites)

A summary with detailed information can be found in:
  ./bin/ab/summary
TOP 10 slowest tests
samba.tests.emulate.traffic_packet(ad_dc_ntvfs) -> 145
samba4.raw.notify(ad_dc_ntvfs) -> 115
samba4.smb2.oplock(ad_dc_ntvfs) -> 103
samba4.nbt.winsreplication(ad_dc_ntvfs) -> 75
samba4.blackbox.pkinit(ad_dc_ntvfs:local)(ad_dc_ntvfs:local) -> 72
samba.tests.samba_tool.gpo(ad_dc_ntvfs:local) -> 65
samba4.ntvfs.cifs.krb5.base.deny2(ad_dc_ntvfs) -> 61
samba4.base.deny2(ad_dc_ntvfs) -> 59
samba4.raw.oplock(ad_dc_ntvfs) -> 58
samba4.ntvfs.cifs.krb5.base.deny1(ad_dc_ntvfs) -> 54
ERROR: test failed with exit code 1
Makefile:16: recipe for target 'test' failed