swarmbucket: fix empty dimension value

appengine/cr-buildbucket/swarming/test/swarming_test.py

 # Copyright 2015 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import base64
 import contextlib
 import datetime
 import json
 
 from components import auth
@@ skipping 22 matching lines @@
 class SwarmingTest(testing.AppengineTestCase):
   def setUp(self):
     super(SwarmingTest, self).setUp()
     self.mock(utils, 'utcnow', lambda: datetime.datetime(2015, 11, 30))
     self.bucket_cfg = project_config_pb2.Bucket(
       name='bucket',
       swarming=project_config_pb2.Swarming(
         hostname='chromium-swarm.appspot.com',
         url_format='https://example.com/{swarming_hostname}/{task_id}',
         common_swarming_tags=['commontag:yes'],
-        common_dimensions=['cores:8', 'pool:default'],
+        common_dimensions=['cores:8', 'pool:default', 'cpu:x86-64'],
         common_recipe=project_config_pb2.Swarming.Recipe(
           repository='https://example.com/repo',
           name='recipe',
         ),
         builders=[
           project_config_pb2.Swarming.Builder(
               name='builder',
               swarming_tags=['buildertag:yes'],
-              dimensions=['os:Linux', 'pool:Chrome'],
+              dimensions=['os:Linux', 'pool:Chrome', 'cpu:'],
               recipe=project_config_pb2.Swarming.Recipe(
                   properties=['predefined-property:x'],
                   properties_j=['predefined-property-bool:true'],
               ),
               priority=108,
           ),
         ],
       ),
     )
     self.mock(
@@ skipping 556 matching lines @@
     self.assertEqual(build.status, model.BuildStatus.COMPLETED)
     self.assertEqual(build.result, model.BuildResult.FAILURE)
     self.assertEqual(build.failure_reason, model.FailureReason.INFRA_FAILURE)
     self.assertIsNotNone(build.result_details)
     self.assertIsNone(build.lease_key)
     self.assertIsNotNone(build.complete_time)
 
 
 def b64json(data):
   return base64.b64encode(json.dumps(data))