diff --git a/neutron/common/config.py b/neutron/common/config.py
index c8e4eebf52c..9911dd69cf0 100644
--- a/neutron/common/config.py
+++ b/neutron/common/config.py
@@ -152,13 +152,18 @@ cfg.CONF.register_cli_opts(core_cli_opts)
 
 # Ensure that the control exchange is set correctly
 oslo_messaging.set_transport_defaults(control_exchange='neutron')
-_SQL_CONNECTION_DEFAULT = 'sqlite://'
-# Update the default QueuePool parameters. These can be tweaked by the
-# configuration variables - max_pool_size, max_overflow and pool_timeout
-db_options.set_defaults(cfg.CONF,
-                        connection=_SQL_CONNECTION_DEFAULT,
-                        sqlite_db='', max_pool_size=10,
-                        max_overflow=20, pool_timeout=10)
+
+
+def set_db_defaults():
+    # Update the default QueuePool parameters. These can be tweaked by the
+    # conf variables - max_pool_size, max_overflow and pool_timeout
+    db_options.set_defaults(
+        cfg.CONF,
+        connection='sqlite://',
+        sqlite_db='', max_pool_size=10,
+        max_overflow=20, pool_timeout=10)
+
+set_db_defaults()
 
 NOVA_CONF_SECTION = 'nova'
 
diff --git a/neutron/tests/base.py b/neutron/tests/base.py
index d89be686bf5..cb5fb3ee66f 100644
--- a/neutron/tests/base.py
+++ b/neutron/tests/base.py
@@ -127,6 +127,11 @@ class DietTestCase(testtools.TestCase):
     def setUp(self):
         super(DietTestCase, self).setUp()
 
+        # FIXME(amuller): this must be called in the Neutron unit tests base
+        # class to initialize the DB connection string. Moving this may cause
+        # non-deterministic failures. Bug #1489098 for more info.
+        config.set_db_defaults()
+
         # Configure this first to ensure pm debugging support for setUp()
         debugger = os.environ.get('OS_POST_MORTEM_DEBUGGER')
         if debugger: