public void testCreateNoToPresent() throws Exception {
   RenameProcessor.Factory factory = new RenameProcessor.Factory();
   Map<String, Object> config = new HashMap<>();
   config.put("field", "old_field");
   try {
     factory.create(null, config);
     fail("factory create should have failed");
   } catch (ElasticsearchParseException e) {
     assertThat(e.getMessage(), equalTo("[target_field] required property is missing"));
   }
 }
 public void testCreate() throws Exception {
   RenameProcessor.Factory factory = new RenameProcessor.Factory();
   Map<String, Object> config = new HashMap<>();
   config.put("field", "old_field");
   config.put("target_field", "new_field");
   String processorTag = randomAsciiOfLength(10);
   RenameProcessor renameProcessor = factory.create(processorTag, config);
   assertThat(renameProcessor.getTag(), equalTo(processorTag));
   assertThat(renameProcessor.getField(), equalTo("old_field"));
   assertThat(renameProcessor.getTargetField(), equalTo("new_field"));
 }