Test network_aliases feature

Signed-off-by: Joffrey F <joffrey@docker.com>

compose/config/validation.py

@@ -97,7 +97,7 @@ def match_network_aliases(service_dict):
     for n in aliased_networks:
         if n not in networks:
             raise ConfigurationError(
-                'Network "{0}" is referenced in network_aliases, but is not'
+                'Network "{0}" is referenced in network_aliases, but is not '
                 'declared in the networks list for service "{1}"'.format(
                     n, service_dict.get('name')
                 )

compose/project.py

@@ -73,7 +73,9 @@ class Project(object):
 
             service_dict.pop('networks', None)
             links = project.get_links(service_dict)
-            network_mode = project.get_network_mode(service_dict, service_networks.keys())
+            network_mode = project.get_network_mode(
+                service_dict, list(service_networks.keys())
+            )
             volumes_from = get_volumes_from(project, service_dict)
 
             if config_data.version != V1: