test create from config with duplicate mount points

Signed-off-by: Collins Abitekaniza <abtcolns@gmail.com>

compose/config/config.py

@@ -8,7 +8,7 @@ import os
 import string
 import sys
 from collections import namedtuple
-from operator import itemgetter, attrgetter
+from operator import attrgetter
 
 import six
 import yaml
@@ -844,9 +844,9 @@ def finalize_service_volumes(service_dict, environment):
                 duplicate_mounts.append(mount.repr())
 
         if duplicate_mounts:
-            raise ConfigurationError("Duplicate mount points: volumes [%s]" % (
+            raise ConfigurationError("Duplicate mount points: [%s]" % (
                 ', '.join(duplicate_mounts)))
-        
+
         service_dict['volumes'] = finalized_volumes
 
     return service_dict

compose/service.py

@@ -9,7 +9,6 @@ import sys
 from collections import namedtuple
 from collections import OrderedDict
 from operator import attrgetter
-from operator import itemgetter
 
 import enum
 import six

tests/unit/config/config_test.py

@@ -3071,6 +3071,41 @@ class ConfigTest(unittest.TestCase):
         )
         config.load(config_details)
 
+    def test_config_duplicate_mount_points(self):
+        config1 = build_config_details(
+            {
+                'version': '3.5',
+                'services': {
+                    'web': {
+                        'image': 'busybox',
+                        'volumes': ['/tmp/foo:/tmp/foo', '/tmp/foo:/tmp/foo:rw']
+                    }
+                }
+            }
+        )
+
+        config2 = build_config_details(
+            {
+                'version': '3.5',
+                'services': {
+                    'web': {
+                        'image': 'busybox',
+                        'volumes': ['/x:/y', '/z:/y']
+                    }
+                }
+            }
+        )
+
+        with self.assertRaises(ConfigurationError) as e:
+            config.load(config1)
+        self.assertEquals(str(e.exception), 'Duplicate mount points: [%s]' % (
+            ', '.join(['/tmp/foo:/tmp/foo:rw']*2)))
+
+        with self.assertRaises(ConfigurationError) as e:
+            config.load(config2)
+        self.assertEquals(str(e.exception), 'Duplicate mount points: [%s]' % (
+            ', '.join(['/x:/y:rw', '/z:/y:rw'])))
+
 
 class NetworkModeTest(unittest.TestCase):