s4:drs:test:getncchanges: add a timeout failure

In the next commit we are going to add tests in which the client
modifies the highwatermark in a way that resets replication (on Samba
only). After that we'll fix it.

If we leave the test in an eternal loop, the commit history will not
be bisectable, so we are temporarily going to turn long waits into
failures.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=15701

Signed-off-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
Reviewed-by: Jennifer Sutton <josutton@catalyst.net.nz>
(cherry picked from commit 4b4a7c3fd465267c43d9586ab79ca8f84c0cad24)

source4/torture/drs/python/getncchanges.py

@@ -33,6 +33,7 @@ import samba.tests
 import ldb
 from ldb import SCOPE_BASE
 import random
+import time
 
 from samba.dcerpc import drsuapi, misc
 from samba import WERRORError
@@ -57,6 +58,7 @@ class DrsReplicaSyncIntegrityTestCase(drs_base.DrsBaseTestCase):
 
         self.default_conn = DcConnection(self, self.ldb_dc2, self.dnsname_dc2)
         self.set_dc_connection(self.default_conn)
+        self.start_time = time.time()
 
     def init_test_state(self):
         self.rxd_dn_list = []
@@ -358,6 +360,9 @@ class DrsReplicaSyncIntegrityTestCase(drs_base.DrsBaseTestCase):
 
     def replication_complete(self):
         """Returns True if the current/last replication cycle is complete"""
+        now = time.time()
+        if now - self.start_time > 30:
+            self.fail("we seem to be in an eternal loop")
 
         if self.last_ctr is None or self.last_ctr.more_data:
             return False