Extend the DESCRIBE_VOLUMES_RESPONSE to include the tagSet as documented by AWS on http://docs.aws.amazon.com/AWSEC2/latest/APIReference/ApiReference-ItemType-DescribeVolumesSetItemResponseType.html . This is needed to pass the test that was added in previous commit.

moto/ec2/models.py

@@ -1255,6 +1255,10 @@ class Volume(object):
         else:
             return 'available'
 
+    def get_tags(self):
+        tags = ec2_backend.describe_tags(filters={'resource-id': [self.id]})
+        return tags
+
 
 class Snapshot(object):
     def __init__(self, snapshot_id, volume, description):

moto/ec2/responses/elastic_block_store.py

@@ -132,6 +132,16 @@ DESCRIBE_VOLUMES_RESPONSE = """<DescribeVolumesResponse xmlns="http://ec2.amazon
                     </item>
                 {% endif %}
              </attachmentSet>
+             <tagSet>
+               {% for tag in volume.get_tags() %}
+                 <item>
+                   <resourceId>{{ tag.resource_id }}</resourceId>
+                   <resourceType>{{ tag.resource_type }}</resourceType>
+                   <key>{{ tag.key }}</key>
+                   <value>{{ tag.value }}</value>
+                 </item>
+               {% endfor %}
+             </tagSet>
              <volumeType>standard</volumeType>
           </item>
       {% endfor %}