diff --git a/nova/tests/unit/compute/test_compute.py b/nova/tests/unit/compute/test_compute.py
index 2caacece232c..935e1dd0287a 100644
--- a/nova/tests/unit/compute/test_compute.py
+++ b/nova/tests/unit/compute/test_compute.py
@@ -87,6 +87,7 @@ from nova.tests.unit.objects import test_flavor
 from nova.tests.unit.objects import test_instance_numa_topology
 from nova.tests.unit.objects import test_migration
 from nova.tests.unit import utils as test_utils
+from nova.tests import uuidsentinel as uuids
 from nova import utils
 from nova.virt import block_device as driver_block_device
 from nova.virt import event
@@ -10956,7 +10957,8 @@ class ComputePolicyTestCase(BaseTestCase):
                  "network:validate_networks": []}
         self.policy.set_rules(rules)
 
-        self.compute_api.create(self.context, None, '1',
+        self.compute_api.create(self.context, None,
+                                image_href=uuids.host_instance,
                                 availability_zone='1:1')
 
 
diff --git a/nova/tests/unit/compute/test_compute_cells.py b/nova/tests/unit/compute/test_compute_cells.py
index 62e2cf0596ae..e4376cce7a22 100644
--- a/nova/tests/unit/compute/test_compute_cells.py
+++ b/nova/tests/unit/compute/test_compute_cells.py
@@ -39,6 +39,7 @@ from nova import test
 from nova.tests.unit.compute import test_compute
 from nova.tests.unit import fake_instance
 from nova.tests.unit.objects import test_flavor
+from nova.tests import uuidsentinel as uuids
 
 
 ORIG_COMPUTE_API = None
@@ -196,7 +197,8 @@ class CellsComputeAPITestCase(test_compute.ComputeAPITestCase):
         # it will raise ObjectActionError if the instance has already
         # been deleted by a instance_destroy_at_top, and instance.refresh()
         # will raise InstanceNotFound
-        instance = objects.Instance(uuid='fake-uuid', cell_name=None)
+        instance = objects.Instance(uuid=uuids.destroy_instance,
+                                    cell_name=None)
         actionerror = exception.ObjectActionError(action='destroy', reason='')
         notfound = exception.InstanceNotFound(instance_id=instance.uuid)
 
@@ -223,7 +225,7 @@ class CellsComputeAPITestCase(test_compute.ComputeAPITestCase):
         # lookup before instance.destroy() is reached, if the instance has
         # already been deleted by a instance_destroy_at_top,
         # InstanceNotFound will be raised
-        instance = objects.Instance(uuid='fake-uuid', cell_name=None)
+        instance = objects.Instance(uuid=uuids.delete_instance, cell_name=None)
         notfound = exception.InstanceNotFound(instance_id=instance.uuid)
 
         @mock.patch.object(compute_api.API, 'delete')
diff --git a/nova/tests/unit/compute/test_compute_utils.py b/nova/tests/unit/compute/test_compute_utils.py
index 80d57028ed82..4142a21e77f1 100644
--- a/nova/tests/unit/compute/test_compute_utils.py
+++ b/nova/tests/unit/compute/test_compute_utils.py
@@ -48,6 +48,7 @@ from nova.tests.unit import fake_server_actions
 import nova.tests.unit.image.fake
 from nova.tests.unit.objects import test_flavor
 from nova.tests.unit.objects import test_migration
+from nova.tests import uuidsentinel as uuids
 from nova.virt import driver
 
 CONF = cfg.CONF
@@ -237,7 +238,8 @@ class DefaultDeviceNamesForInstanceTestCase(test.NoDBTestCase):
         self.ephemerals = block_device_obj.block_device_make_list(
                 self.context,
                 [fake_block_device.FakeDbBlockDeviceDict(
-                 {'id': 1, 'instance_uuid': 'fake-instance',
+                 {'id': 1,
+                  'instance_uuid': uuids.block_device_instance,
                   'device_name': '/dev/vdb',
                   'source_type': 'blank',
                   'destination_type': 'local',
@@ -248,7 +250,8 @@ class DefaultDeviceNamesForInstanceTestCase(test.NoDBTestCase):
         self.swap = block_device_obj.block_device_make_list(
                 self.context,
                 [fake_block_device.FakeDbBlockDeviceDict(
-                 {'id': 2, 'instance_uuid': 'fake-instance',
+                 {'id': 2,
+                  'instance_uuid': uuids.block_device_instance,
                   'device_name': '/dev/vdc',
                   'source_type': 'blank',
                   'destination_type': 'local',
@@ -259,26 +262,30 @@ class DefaultDeviceNamesForInstanceTestCase(test.NoDBTestCase):
         self.block_device_mapping = block_device_obj.block_device_make_list(
                 self.context,
                 [fake_block_device.FakeDbBlockDeviceDict(
-                 {'id': 3, 'instance_uuid': 'fake-instance',
+                 {'id': 3,
+                  'instance_uuid': uuids.block_device_instance,
                   'device_name': '/dev/vda',
                   'source_type': 'volume',
                   'destination_type': 'volume',
                   'volume_id': 'fake-volume-id-1',
                   'boot_index': 0}),
                  fake_block_device.FakeDbBlockDeviceDict(
-                 {'id': 4, 'instance_uuid': 'fake-instance',
+                 {'id': 4,
+                  'instance_uuid': uuids.block_device_instance,
                   'device_name': '/dev/vdd',
                   'source_type': 'snapshot',
                   'destination_type': 'volume',
                   'snapshot_id': 'fake-snapshot-id-1',
                   'boot_index': -1}),
                  fake_block_device.FakeDbBlockDeviceDict(
-                 {'id': 5, 'instance_uuid': 'fake-instance',
+                 {'id': 5,
+                  'instance_uuid': uuids.block_device_instance,
                   'device_name': '/dev/vde',
                   'source_type': 'blank',
                   'destination_type': 'volume',
                   'boot_index': -1})])
-        self.instance = {'uuid': 'fake_instance', 'ephemeral_gb': 2}
+        self.instance = {'uuid': uuids.instance,
+                         'ephemeral_gb': 2}
         self.is_libvirt = False
         self.root_device_name = '/dev/vda'
         self.update_called = False