anchor.diff:  
   [source,js]
   --------------------------------------------------
  -curl -XPUT 'localhost:9200/users' -d '{
  +PUT /users
  +{
       "mappings" : {
           "user" : {
               "properties" : {
  
positive.code: 
  [source,js]
  --------------------------------------------------
  curl -XPOST 'http://localhost:9200/_aliases' -d '
  {
      "actions" : [
          { "remove" : { "index" : "test1", "alias" : "alias1" } },
          { "add" : { "index" : "test1", "alias" : "alias2" } }
      ]
  }'
  --------------------------------------------------
  
  Associating an alias with more than one index are simply several `add`
  actions:
  
  [source,js]
  --------------------------------------------------
  curl -XPOST 'http://localhost:9200/_aliases' -d '
  {
      "actions" : [
          { "add" : { "index" : "test1", "alias" : "alias1" } },
          { "add" : { "index" : "test2", "alias" : "alias1" } }
      ]
  }'
  --------------------------------------------------
  
  Multiple indices can be specified for an action with the `indices` array syntax:
  
  [source,js]
  --------------------------------------------------
  curl -XPOST 'http://localhost:9200/_aliases' -d '
  {
      "actions" : [
          { "add" : { "indices" : ["test1", "test2"], "alias" : "alias1" } }
      ]
  }'
  --------------------------------------------------
  
  To specify multiple aliases in one action, the corresponding `aliases` array
  syntax exists as well.
  
negative.code: 
  [source,js]
  --------------------------------------------------
  POST /_aliases
  {
      "actions" : [
          { "add" : { "index" : "test1", "alias" : "alias1" } }
      ]
  }
  --------------------------------------------------
  // CONSOLE
  // TEST[s/^/PUT test1\n/]
  
  An alias can also be removed, for example:
  
  [source,js]
  --------------------------------------------------
  POST /_aliases
  {
      "actions" : [
          { "remove" : { "index" : "test1", "alias" : "alias1" } }
      ]
  }
  --------------------------------------------------
  // CONSOLE
  // TEST[continued]
  
  Renaming an alias is a simple `remove` then `add` operation within the
  same API. This operation is atomic, no need to worry about a short
  