tests: Move repeated code into a helper function

Several tests hang all the objects they create off a unique OU.
Having a common OU makes cleanup easier, and having a unique OU (i.e.
adding some randomness) helps protect against one-off test failures
(Replication between testenvs is happening in the background.
Occasionally, when a test finishes on one testenv and moves onto the
next testenv, that testenv may have received the replicated test
objects from the first testenv, but has not received their deletion
yet).

Rather than copy-n-pasting this code yet again, split it out into a
helper function.

Reviewed-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Garming Sam <garming@catalyst.net.nz>
Signed-off-by: Tim Beale <timbeale@catalyst.net.nz>

python/samba/tests/__init__.py

@@ -36,6 +36,7 @@ import re
 import samba.auth
 import samba.dcerpc.base
 from samba.compat import PY3, text_type
+from random import randint
 if not PY3:
     # Py2 only
     from samba.samdb import SamDB
@@ -475,3 +476,15 @@ def delete_force(samdb, dn, **kwargs):
     except ldb.LdbError as error:
         (num, errstr) = error.args
         assert num == ldb.ERR_NO_SUCH_OBJECT, "ldb.delete() failed: %s" % errstr
+
+def create_test_ou(samdb, name):
+    """Creates a unique OU for the test"""
+
+    # Add some randomness to the test OU. Replication between the testenvs is
+    # constantly happening in the background. Deletion of the last test's
+    # objects can be slow to replicate out. So the OU created by a previous
+    # testenv may still exist at the point that tests start on another testenv.
+    rand = randint(1, 10000000)
+    dn = "OU=%s%d,%s" %(name, rand, samdb.get_default_basedn())
+    samdb.add({ "dn": dn, "objectclass": "organizationalUnit"})
+    return dn