You can test that your Elasticsearch node is running by sending an HTTP request to port 9200 on localhost:

GET /
which should give you a response something like this:
{
  "name" : "Cp8oag6",
  "cluster_name" : "elasticsearch",
  "cluster_uuid" : "AT69_T_DTp-1qgIJlatQqA",
  "version" : {
    "number" : "5.1.2",
    "build_hash" : "f27399d",
    "build_date" : "2016-03-30T09:51:41.449Z",
    "build_snapshot" : false,
    "lucene_version" : "6.3.0"
  },
  "tagline" : "You Know, for Search"
}
Source:
Example:cth-nak-test