diff --git a/lib/xos-synchronizer/tests/test_payload.py b/lib/xos-synchronizer/tests/test_payload.py
new file mode 100644
index 0000000..6bd1cfc
--- /dev/null
+++ b/lib/xos-synchronizer/tests/test_payload.py
@@ -0,0 +1,346 @@
+# 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 json
+import unittest
+from mock import patch
+import mock
+import pdb
+import networkx as nx
+
+import os
+import sys
+
+test_path = os.path.abspath(os.path.dirname(os.path.realpath(__file__)))
+sync_lib_dir = os.path.join(test_path, "..", "xossynchronizer")
+xos_dir = os.path.join(test_path, "..", "..", "..", "xos")
+
+ANSIBLE_FILE = "/tmp/payload_test"
+
+log = None
+
+
+def run_fake_ansible_template(*args, **kwargs):
+    opts = args[1]
+    open(ANSIBLE_FILE, "w").write(json.dumps(opts))
+    return [{"rc": 0}]
+
+
+def run_fake_ansible_template_fail(*args, **kwargs):
+    opts = args[1]
+    open(ANSIBLE_FILE, "w").write(json.dumps(opts))
+    return [{"rc": 1}]
+
+
+def get_ansible_output():
+    ansible_str = open(ANSIBLE_FILE).read()
+    return json.loads(ansible_str)
+
+
+class TestPayload(unittest.TestCase):
+    @classmethod
+    def setUpClass(cls):
+
+        global log
+
+        config = os.path.join(test_path, "test_config.yaml")
+        from xosconfig import Config
+
+        Config.clear()
+        Config.init(config, "synchronizer-config-schema.yaml")
+
+        if not log:
+            from multistructlog import create_logger
+
+            log = create_logger(Config().get("logging"))
+
+    def setUp(self):
+
+        global log, steps, event_loop
+
+        self.sys_path_save = sys.path
+        self.cwd_save = os.getcwd()
+
+        config = os.path.join(test_path, "test_config.yaml")
+        from xosconfig import Config
+
+        Config.clear()
+        Config.init(config, "synchronizer-config-schema.yaml")
+
+        from xossynchronizer.mock_modelaccessor_build import (
+            build_mock_modelaccessor,
+        )
+
+        build_mock_modelaccessor(sync_lib_dir, xos_dir, services_dir=None, service_xprotos=[])
+
+        os.chdir(os.path.join(test_path, ".."))  # config references tests/model-deps
+
+        import xossynchronizer.event_loop
+
+        reload(xossynchronizer.event_loop)
+        import xossynchronizer.backend
+
+        reload(xossynchronizer.backend)
+        import steps.sync_instances
+        import steps.sync_controller_slices
+        from xossynchronizer.modelaccessor import model_accessor
+
+        # import all class names to globals
+        for (k, v) in model_accessor.all_model_classes.items():
+            globals()[k] = v
+        b = xossynchronizer.backend.Backend()
+        steps_dir = Config.get("steps_dir")
+        self.steps = b.load_sync_step_modules(steps_dir)
+        self.synchronizer = xossynchronizer.event_loop.XOSObserver(self.steps)
+
+    def tearDown(self):
+        sys.path = self.sys_path_save
+        os.chdir(self.cwd_save)
+
+    @mock.patch(
+        "steps.sync_instances.syncstep.run_template",
+        side_effect=run_fake_ansible_template,
+    )
+    @mock.patch("xossynchronizer.event_loop.model_accessor")
+    def test_delete_record(self, mock_run_template, mock_modelaccessor):
+        with mock.patch.object(Instance, "save") as instance_save:
+            o = Instance()
+            o.name = "Sisi Pascal"
+
+            o.synchronizer_step = steps.sync_instances.SyncInstances()
+            self.synchronizer.delete_record(o, log)
+
+            a = get_ansible_output()
+            self.assertDictContainsSubset({"delete": True, "name": o.name}, a)
+            o.save.assert_called_with(update_fields=["backend_need_reap"])
+
+    @mock.patch(
+        "steps.sync_instances.syncstep.run_template",
+        side_effect=run_fake_ansible_template_fail,
+    )
+    @mock.patch("xossynchronizer.event_loop.model_accessor")
+    def test_delete_record_fail(self, mock_run_template, mock_modelaccessor):
+        with mock.patch.object(Instance, "save") as instance_save:
+            o = Instance()
+            o.name = "Sisi Pascal"
+
+            o.synchronizer_step = steps.sync_instances.SyncInstances()
+
+            with self.assertRaises(Exception) as e:
+                self.synchronizer.delete_record(o, log)
+
+            self.assertEqual(
+                e.exception.message, "Nonzero rc from Ansible during delete_record"
+            )
+
+    @mock.patch(
+        "steps.sync_instances.syncstep.run_template",
+        side_effect=run_fake_ansible_template,
+    )
+    @mock.patch("xossynchronizer.event_loop.model_accessor")
+    def test_sync_record(self, mock_run_template, mock_modelaccessor):
+        with mock.patch.object(Instance, "save") as instance_save:
+            o = Instance()
+            o.name = "Sisi Pascal"
+
+            o.synchronizer_step = steps.sync_instances.SyncInstances()
+            self.synchronizer.sync_record(o, log)
+
+            a = get_ansible_output()
+            self.assertDictContainsSubset({"delete": False, "name": o.name}, a)
+            o.save.assert_called_with(
+                update_fields=[
+                    "enacted",
+                    "backend_status",
+                    "backend_register",
+                    "backend_code",
+                ]
+            )
+
+    @mock.patch(
+        "steps.sync_instances.syncstep.run_template",
+        side_effect=run_fake_ansible_template,
+    )
+    @mock.patch("xossynchronizer.event_loop.model_accessor")
+    def test_sync_cohort(self, mock_run_template, mock_modelaccessor):
+        with mock.patch.object(Instance, "save") as instance_save, mock.patch.object(
+            ControllerSlice, "save"
+        ) as controllerslice_save:
+            cs = ControllerSlice()
+            s = Slice(name="SP SP")
+            cs.slice = s
+
+            o = Instance()
+            o.name = "Sisi Pascal"
+            o.slice = s
+
+            cohort = [cs, o]
+            o.synchronizer_step = steps.sync_instances.SyncInstances()
+            cs.synchronizer_step = steps.sync_controller_slices.SyncControllerSlices()
+
+            self.synchronizer.sync_cohort(cohort, False)
+
+            a = get_ansible_output()
+            self.assertDictContainsSubset({"delete": False, "name": o.name}, a)
+            o.save.assert_called_with(
+                update_fields=[
+                    "enacted",
+                    "backend_status",
+                    "backend_register",
+                    "backend_code",
+                ]
+            )
+            cs.save.assert_called_with(
+                update_fields=[
+                    "enacted",
+                    "backend_status",
+                    "backend_register",
+                    "backend_code",
+                ]
+            )
+
+    @mock.patch(
+        "steps.sync_instances.syncstep.run_template",
+        side_effect=run_fake_ansible_template,
+    )
+    @mock.patch("xossynchronizer.event_loop.model_accessor")
+    def test_deferred_exception(self, mock_run_template, mock_modelaccessor):
+        with mock.patch.object(Instance, "save") as instance_save:
+            cs = ControllerSlice()
+            s = Slice(name="SP SP")
+            cs.slice = s
+            cs.force_defer = True
+
+            o = Instance()
+            o.name = "Sisi Pascal"
+            o.slice = s
+
+            cohort = [cs, o]
+            o.synchronizer_step = steps.sync_instances.SyncInstances()
+            cs.synchronizer_step = steps.sync_controller_slices.SyncControllerSlices()
+
+            self.synchronizer.sync_cohort(cohort, False)
+            o.save.assert_called_with(
+                always_update_timestamp=True,
+                update_fields=["backend_status", "backend_register"],
+            )
+            self.assertEqual(cs.backend_code, 0)
+
+            self.assertIn("Force", cs.backend_status)
+            self.assertIn("Failed due to", o.backend_status)
+
+    @mock.patch(
+        "steps.sync_instances.syncstep.run_template",
+        side_effect=run_fake_ansible_template,
+    )
+    @mock.patch("xossynchronizer.event_loop.model_accessor")
+    def test_backend_status(self, mock_run_template, mock_modelaccessor):
+        with mock.patch.object(Instance, "save") as instance_save:
+            cs = ControllerSlice()
+            s = Slice(name="SP SP")
+            cs.slice = s
+            cs.force_fail = True
+
+            o = Instance()
+            o.name = "Sisi Pascal"
+            o.slice = s
+
+            cohort = [cs, o]
+            o.synchronizer_step = steps.sync_instances.SyncInstances()
+            cs.synchronizer_step = steps.sync_controller_slices.SyncControllerSlices()
+
+            self.synchronizer.sync_cohort(cohort, False)
+            o.save.assert_called_with(
+                always_update_timestamp=True,
+                update_fields=["backend_status", "backend_register"],
+            )
+            self.assertIn("Force", cs.backend_status)
+            self.assertIn("Failed due to", o.backend_status)
+
+    @mock.patch(
+        "steps.sync_instances.syncstep.run_template",
+        side_effect=run_fake_ansible_template,
+    )
+    @mock.patch("xossynchronizer.event_loop.model_accessor")
+    def test_fetch_pending(self, mock_run_template, mock_accessor, *_other_accessors):
+        pending_objects, pending_steps = self.synchronizer.fetch_pending()
+        pending_objects2 = list(pending_objects)
+
+        any_cs = next(
+            obj for obj in pending_objects if obj.leaf_model_name == "ControllerSlice"
+        )
+        any_instance = next(
+            obj for obj in pending_objects2 if obj.leaf_model_name == "Instance"
+        )
+
+        slice = Slice()
+        any_instance.slice = slice
+        any_cs.slice = slice
+
+        self.synchronizer.external_dependencies = []
+        cohorts = self.synchronizer.compute_dependent_cohorts(pending_objects, False)
+        flat_objects = [item for cohort in cohorts for item in cohort]
+
+        self.assertEqual(set(flat_objects), set(pending_objects))
+
+    @mock.patch(
+        "steps.sync_instances.syncstep.run_template",
+        side_effect=run_fake_ansible_template,
+    )
+    @mock.patch("xossynchronizer.event_loop.model_accessor")
+    def test_fetch_pending_with_external_dependencies(
+        self, mock_run_template, mock_accessor, *_other_accessors
+    ):
+        pending_objects, pending_steps = self.synchronizer.fetch_pending()
+        pending_objects2 = list(pending_objects)
+
+        any_cn = next(
+            obj for obj in pending_objects if obj.leaf_model_name == "ControllerNetwork"
+        )
+        any_user = next(
+            obj for obj in pending_objects2 if obj.leaf_model_name == "User"
+        )
+
+        cohorts = self.synchronizer.compute_dependent_cohorts(pending_objects, False)
+
+        flat_objects = [item for cohort in cohorts for item in cohort]
+        self.assertEqual(set(flat_objects), set(pending_objects))
+
+        # These cannot be None, but for documentation purposes
+        self.assertIsNotNone(any_cn)
+        self.assertIsNotNone(any_user)
+
+    @mock.patch(
+        "steps.sync_instances.syncstep.run_template",
+        side_effect=run_fake_ansible_template,
+    )
+    @mock.patch("xossynchronizer.event_loop.model_accessor")
+    def test_external_dependency_exception(self, mock_run_template, mock_modelaccessor):
+        cs = ControllerSlice()
+        s = Slice(name="SP SP")
+        cs.slice = s
+
+        o = Instance()
+        o.name = "Sisi Pascal"
+        o.slice = s
+
+        cohort = [cs, o]
+        o.synchronizer_step = None
+        o.synchronizer_step = steps.sync_instances.SyncInstances()
+
+        self.synchronizer.sync_cohort(cohort, False)
+
+
+if __name__ == "__main__":
+    unittest.main()