diff --git a/xos/synchronizer/test_helpers.py b/xos/synchronizer/test_helpers.py
new file mode 100644
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--- /dev/null
+++ b/xos/synchronizer/test_helpers.py
@@ -0,0 +1,163 @@
+# Copyright 2017-present Open Networking Foundation
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import unittest
+from mock import patch, call, Mock, PropertyMock
+import json
+
+import os, sys
+
+test_path=os.path.abspath(os.path.dirname(os.path.realpath(__file__)))
+
+
+class TestTtHelpers(unittest.TestCase):
+
+    def setUp(self):
+
+        self.sys_path_save = sys.path
+
+        # Setting up the config module
+        from xosconfig import Config
+        config = os.path.join(test_path, "test_config.yaml")
+        Config.clear()
+        Config.init(config, "synchronizer-config-schema.yaml")
+        # END Setting up the config module
+
+        from multistructlog import create_logger
+        self.log = create_logger(Config().get('logging'))
+
+        from xossynchronizer.mock_modelaccessor_build import mock_modelaccessor_config
+        mock_modelaccessor_config(test_path, [("tt-workflow-driver", "tt-workflow-driver.xproto"),
+                                              ("olt-service", "volt.xproto"),
+                                              ("rcord", "rcord.xproto")])
+
+        import xossynchronizer.modelaccessor
+        import mock_modelaccessor
+        reload(mock_modelaccessor) # in case nose2 loaded it in a previous test
+        reload(xossynchronizer.modelaccessor)      # in case nose2 loaded it in a previous test
+
+        from xossynchronizer.modelaccessor import model_accessor
+        from helpers import TtHelpers
+
+        # import all class names to globals
+        for (k, v) in model_accessor.all_model_classes.items():
+            globals()[k] = v
+
+        self.helpers = TtHelpers
+        self.model_accessor = model_accessor
+
+        self._volt = VOLTService()
+        self._volt.id = 1
+
+        self.volt = Service()
+        self.volt.id = 1
+        self.volt.name = "vOLT"
+        self.volt.leaf_model = self._volt
+
+        self.pon_port = PONPort()
+        self.pon_port.port_no = 1234
+
+        self.onu = ONUDevice()
+        self.onu.pon_port = self.pon_port
+        self.onu.serial_number = "BRCM1234"
+
+        self.tt_si = TtWorkflowDriverServiceInstance(
+            serial_number="BRCM1234",
+            owner=self.volt,
+            owner_id=self.volt.id,
+            of_dpid="of:1234"
+        )
+
+        self.whitelist_entry = TtWorkflowDriverWhiteListEntry(
+            serial_number="BRCM1234",
+            owner=self.volt,
+            owner_id=self.volt.id,
+            pon_port_id=1234,
+            device_id="of:1234"
+        )
+
+
+    def tearDown(self):
+        sys.path = self.sys_path_save
+
+    def test_not_in_whitelist(self):
+
+        with patch.object(TtWorkflowDriverWhiteListEntry.objects, "get_items") as whitelist_mock:
+            whitelist_mock.return_value = []
+
+            [res, message] = self.helpers.validate_onu(self.model_accessor, self.log, self.tt_si)
+
+            self.assertFalse(res)
+            self.assertEqual(message, "ONU not found in whitelist")
+
+    def test_wrong_location_port(self):
+        self.pon_port.port_no = 666
+        with patch.object(TtWorkflowDriverWhiteListEntry.objects, "get_items") as whitelist_mock, \
+            patch.object(ONUDevice.objects, "get_items") as onu_mock:
+            whitelist_mock.return_value = [self.whitelist_entry]
+            onu_mock.return_value = [self.onu]
+
+            [res, message] = self.helpers.validate_onu(self.model_accessor, self.log, self.tt_si)
+
+            self.assertFalse(res)
+            self.assertEqual(message, "ONU activated in wrong location")
+
+    def test_wrong_location_device(self):
+        self.tt_si.of_dpid = 666
+        with patch.object(TtWorkflowDriverWhiteListEntry.objects, "get_items") as whitelist_mock, \
+            patch.object(ONUDevice.objects, "get_items") as onu_mock:
+            whitelist_mock.return_value = [self.whitelist_entry]
+            onu_mock.return_value = [self.onu]
+
+            [res, message] = self.helpers.validate_onu(self.model_accessor, self.log, self.tt_si)
+
+            self.assertFalse(res)
+            self.assertEqual(message, "ONU activated in wrong location")
+
+    def test_deferred_validation(self):
+        with patch.object(TtWorkflowDriverWhiteListEntry.objects, "get_items") as whitelist_mock, \
+            patch.object(ONUDevice.objects, "get_items") as onu_mock:
+            whitelist_mock.return_value = [self.whitelist_entry]
+            onu_mock.return_value = []
+
+            with self.assertRaises(Exception) as e:
+                self.helpers.validate_onu(self.model_accessor, self.log, self.tt_si)
+
+            self.assertEqual(e.exception.message, "ONU device %s is not know to XOS yet" % self.tt_si.serial_number)
+
+    def test_validating_onu(self):
+        with patch.object(TtWorkflowDriverWhiteListEntry.objects, "get_items") as whitelist_mock, \
+            patch.object(ONUDevice.objects, "get_items") as onu_mock:
+            whitelist_mock.return_value = [self.whitelist_entry]
+            onu_mock.return_value = [self.onu]
+
+            [res, message] = self.helpers.validate_onu(self.model_accessor, self.log, self.tt_si)
+
+            self.assertTrue(res)
+            self.assertEqual(message, "ONU has been validated")
+
+    def test_validating_onu_lowercase(self):
+        self.whitelist_entry.serial_number = "brcm1234"
+        with patch.object(TtWorkflowDriverWhiteListEntry.objects, "get_items") as whitelist_mock, \
+            patch.object(ONUDevice.objects, "get_items") as onu_mock:
+            whitelist_mock.return_value = [self.whitelist_entry]
+            onu_mock.return_value = [self.onu]
+
+            [res, message] = self.helpers.validate_onu(self.model_accessor, self.log, self.tt_si)
+
+            self.assertTrue(res)
+            self.assertEqual(message, "ONU has been validated")
+
+if __name__ == '__main__':
+    unittest.main()
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