diff --git a/nova/test.py b/nova/test.py
index 2d225737c079..92befa9c782e 100644
--- a/nova/test.py
+++ b/nova/test.py
@@ -435,6 +435,25 @@ class TestCase(testtools.TestCase):
         compute.manager._resource_tracker = None
         compute.start()
 
+    @staticmethod
+    def restart_scheduler_service(scheduler):
+        """Restart a scheduler service in a realistic way.
+
+        Deals with resetting the host state cache in the case of using the
+        CachingScheduler driver.
+
+        :param scheduler: The nova-scheduler service to be restarted.
+        """
+        scheduler.stop()
+        if hasattr(scheduler.manager.driver, 'all_host_states'):
+            # On startup, the CachingScheduler runs a periodic task to pull
+            # the initial set of compute nodes out of the database which it
+            # then puts into a cache (hence the name of the driver). This can
+            # race with actually starting the compute services so we need to
+            # restart the scheduler to refresh the cache.
+            scheduler.manager.driver.all_host_states = None
+        scheduler.start()
+
     def assertJsonEqual(self, expected, observed, message=''):
         """Asserts that 2 complex data structures are json equivalent.
 
diff --git a/nova/tests/functional/regressions/test_bug_1671648.py b/nova/tests/functional/regressions/test_bug_1671648.py
index a5b98425f985..c1c0653d7206 100644
--- a/nova/tests/functional/regressions/test_bug_1671648.py
+++ b/nova/tests/functional/regressions/test_bug_1671648.py
@@ -63,7 +63,6 @@ class TestRetryBetweenComputeNodeBuilds(test.TestCase):
 
         self.start_service('conductor')
         self.start_service('consoleauth')
-        self.start_service('scheduler')
 
         # We start two compute services because we're going to fake one
         # of them to fail the build so we can trigger the retry code.
@@ -80,6 +79,10 @@ class TestRetryBetweenComputeNodeBuilds(test.TestCase):
         self.addCleanup(fake.restore_nodes)
         self.start_service('compute', host='host2')
 
+        # Start the scheduler after the compute nodes are created in the DB
+        # in the case of using the CachingScheduler.
+        self.start_service('scheduler')
+
         self.useFixture(cast_as_call.CastAsCall(self))
 
         self.image_id = self.admin_api.get_images()[0]['id']
diff --git a/nova/tests/functional/regressions/test_bug_1741125.py b/nova/tests/functional/regressions/test_bug_1741125.py
index 276d2b0543f2..206a2eda685d 100644
--- a/nova/tests/functional/regressions/test_bug_1741125.py
+++ b/nova/tests/functional/regressions/test_bug_1741125.py
@@ -36,6 +36,9 @@ class TestServerResizeReschedule(integrated_helpers.ProviderUsageBaseTestCase):
         self.compute3 = self._start_compute(host='host3')
         self.compute4 = self._start_compute(host='host4')
 
+        # Restart the scheduler to reset the host state cache.
+        self.restart_scheduler_service(self.scheduler_service)
+
         flavors = self.api.get_flavors()
         self.flavor1 = flavors[0]
         self.flavor2 = flavors[1]
diff --git a/nova/tests/functional/regressions/test_bug_1741307.py b/nova/tests/functional/regressions/test_bug_1741307.py
index df371c94fa6d..0041b95f7505 100644
--- a/nova/tests/functional/regressions/test_bug_1741307.py
+++ b/nova/tests/functional/regressions/test_bug_1741307.py
@@ -59,9 +59,6 @@ class TestResizeWithCachingScheduler(test.TestCase,
         self.addCleanup(nova.tests.unit.image.fake.FakeImageService_reset)
 
         self.start_service('conductor')
-        # Configure the CachingScheduler.
-        self.flags(driver='caching_scheduler', group='scheduler')
-        self.start_service('scheduler')
 
         # Create two compute nodes/services.
         for host in ('host1', 'host2'):
@@ -69,6 +66,11 @@ class TestResizeWithCachingScheduler(test.TestCase,
             self.addCleanup(fake.restore_nodes)
             self.start_service('compute', host=host)
 
+        # Start the scheduler after the compute nodes are created in the DB
+        # in the case of using the CachingScheduler.
+        self.flags(driver='caching_scheduler', group='scheduler')
+        self.start_service('scheduler')
+
         flavors = self.api.get_flavors()
         self.old_flavor = flavors[0]
         self.new_flavor = flavors[1]
diff --git a/nova/tests/functional/test_nova_manage.py b/nova/tests/functional/test_nova_manage.py
index d76eb3693db8..09ddbd16ab01 100644
--- a/nova/tests/functional/test_nova_manage.py
+++ b/nova/tests/functional/test_nova_manage.py
@@ -387,14 +387,8 @@ class TestNovaManagePlacementHealAllocations(
         self.flavor = self.api.get_flavors()[0]
         self.output = StringIO()
         self.useFixture(fixtures.MonkeyPatch('sys.stdout', self.output))
-        # On startup, the CachingScheduler runs a periodic task to pull the
-        # initial set of compute nodes out of the database which it then puts
-        # into a cache (hence the name of the driver). This can race with
-        # actually starting the compute services so we need to restart the
-        # scheduler to refresh the cache.
-        self.scheduler_service.stop()
-        self.scheduler_service.manager.driver.all_host_states = None
-        self.scheduler_service.start()
+        # Restart the scheduler to reset the host state cache.
+        self.restart_scheduler_service(self.scheduler_service)
 
     def _boot_and_assert_no_allocations(self, flavor, hostname):
         """Creates a server on the given host and asserts neither have usage