Give proper ERROR for too large exports

The "api_export_size" quota is currently being
enforced, but it doesn't give a proper ERROR on
the "export" resource. This is due to some bad
exception handling.

Change-Id: Ic27c781a35ea74ba605c05275f6970b44b07b65e
closes-bug: 1566911

designate/tests/unit/test_zone_manager/test_service.py

@@ -20,6 +20,7 @@
 import mock
 from oslotest import base as test
 
+from designate import exceptions
 from designate.tests.unit import RoObject
 import designate.zone_manager.service as zms
 
@@ -79,3 +80,22 @@ class ZoneManagerTest(test.BaseTestCase):
             },
             out
         )
+
+    def test_exceed_size_quota(self, _):
+        context = mock.Mock()
+        export = dict(location=None, id=4)
+        size = 9999999999
+
+        self.tm.quota.limit_check.side_effect = exceptions.OverQuota()
+        out = self.tm._determine_export_method(context, export, size)
+        self.tm.quota.limit_check.side_effect = None
+
+        self.assertDictEqual(
+            {
+                'status': 'ERROR',
+                'id': 4,
+                'location': None,
+                'message': 'Zone is too large to export'
+            },
+            out
+        )

designate/zone_manager/service.py

@@ -125,7 +125,7 @@ class Service(service.RPCService, coordination.CoordinationMixin,
             try:
                 self.quota.limit_check(
                         context, context.tenant, api_export_size=size)
-            except exceptions.OverQuota():
+            except exceptions.OverQuota:
                 LOG.debug('Zone Export too large to perform synchronously')
                 export['status'] = 'ERROR'
                 export['message'] = 'Zone is too large to export'